I am back for a short time before the pear harvest.
I own a pair of the above mentioned 9x35 Stellar brand porros and they are very good. They actually made my grab-&-go shelf by the back door because there aren't many small-ish 9xs (9x63s don't count), and they have a very wide FOV. The old Pentax roofer 9x30s are surprisingly good for tiny bins I can put in my jeans pocket when I'm running out to the back pasture with a shovel because so fool let his stallion pony loose, it's in one of my pastures (thus the bins) trying to get to my quarter horse mares, and my Arabian stallion will kill the little SOB pony. See below a big reason why this Pentax roofer is nice for me.
The 10x50 W I like is either the Yukon 10x50W or the Zeiss Jena Dekaren 10x50 MC 1Q if you can find them and afford them. But it is the 7x35 and 8x30 sizes (+ a few 8x40s) that have huge fields of view.Speaking of Canons and wide views, check out the Canon 6x30 with the magenta classic Canon coatings. The size of the image really starts to get small-ish for me at 6x (although my 6x30 FMTR Fujinon is fabulous for astronomy, because a star should be a point and so a 6x point is just as good as a 7x, 8x, 9x or 10x point). Did I mention the older Fuji Meijis because they are super nice too.
As far as vintage bins and image quality goes, I find that most of the Nikon porro bins like the recent SEs are much better than any roofer ever made and I'm not alone in that judgment. Coatings aren't everything either. For viewing birds in arboretums or aviaries I don't find a huge difference between single and MC. Sometimes old craftsmen took allot of time grinding lens sets that worked incredibly well. Even the vintage Baigish 8x30s are super sharp and according to Holger Merlitz the KOMZ 7x30/10x42-10x40s are about the sharpest bins he's ever seen, so don't discount the Russian bins.
I have always been surprised how well SARD views were when they used nice coatings on their 7x50s in the late 40s and 50s. Usually light transmission isn't a big problem for birding during the Spring/Summer/Early Autumn seasons so coatings aren't always important and less light transmission is sometimes easier on the eyes. Speaking of which, the polarizing filters that came in the kit with the Pentax 9x30 roofers I mentioned above are sheer genius. This filter set improves the view dramatically on bright/glare-y days. I'm used to yellow filters that help the view on overcast (too-blue) days, and Hensoldt NDX4 filters from Hensoldt for desert bins, but polarizers designed for a bin are very helpful on over-bright days.
I recently bought a pair of Russian Fotem 15x50 bins with literature marked 1972. The yellow glass problem is there, and the literature was for the German market. Remarkably the bins came from a group found in the old East Germany, and were all NIB. They are made extremely well, razor sharp and lightweight with magnesium housings. The image is as sharp as the KOMZ 10x42. They have CF and a nice grippy pebble coating. The 3 inch long (75mm) main center bridge seems like it could withstand dropping without coming out of alignment. I am surprised that these bins are so light and sharp and in winter when glare and over-blue-ness is a problem, I will switch out my Yukon 16x50x for this bin. Clearly they are vintage even if they are like new, so I recommend them here. The seller on eBay had 10-12 pairs when I bought mine.
I don't know if I recommended the D&D Czech bins in 6x30 format that were used along the Iron Curtain in years past. Many of these came on the market in the last 4 years and they may be vintage but they often have 1980s MCs on the lenses. The Czech Republic Meopta brand bins are made by many of the previous D&D employees.
I do like many modern porro bins from Zeiss (7x50 Marine), Steiner (9x40 and 7x50), and Nikons SEs. But the vintage porro bins that were made well often had huge FOVs (great for sports), and the center field was very sharp, due to hand polished lenses. Although Leica Trinovids were not phase coated, the Leica Kern porros of the late series were stupendous (as one of the employees who retired from the microscope company currently owning Kern discussed on this forum). The 10x40 habicht was so good and well liked that Swarovski brought it back. Maybe I am one of the 10% of the population who have 4 color peaks instead of 3 peaks of highest color sensitivity and so roofers cannot be made to ever make a view as good as a porro for me, but the lack of really super and ultra wide field bins, I think is very much due to the stampede to roofers that seems unwarranted.
I have the new Kruger waterproof, CF 10x30 porro bin in my hands many days now. It is pretty sharp, low weight, rubberized in a good way, CF, and has excellent MCs. The bin sells for about US$120. If Kruger made a Nikon Se knockoff in a waterproof version (or better with LD glass) and then an ultrawide, so they had 3 different 10x choice (with maybe a 4th in a 10x60 or 10x70 size, as a waterproof model for astronomers with Low Dispersion glass), then I'm sure that all of these bins would sell for hundreds of dollars less than Leica, Swaro or Zeiss roofer models of comparable magnification, sharpness and objective light-gethering.
Maybe the Zeiss 7x50 IF is the best ever astronomy bin ever (or maybe it's the Nikon Prostar or Fujinon FMT), so there seem to be enough 7x50 IFs out there. But a superb 7x50 CF porro would be nice for low light situations (though Pentax makes one the IP distance is way too tiny for my and my friends, but women I know like them). Kruger has a Yosemite competitor now too, so why no waterproof high end 8x30s with LD glass, or ultra-wide 8x30s (like the Hensoldt DF FOV) in CF porro versions.
It is not impossible to make waterproof 7x35 and 8x40 multicoated, wide angle bins with aspherical eyepieces because Nikon does this now. Why not an ultra high end version of the Extreme Action 7x35s and 8x40s (or an 8x30 UW Extreme Action). Roofers are greatly over rated and over priced from what I can see in testing them here at the ranch. This was incredibly obvious before phase coatings came along and so manufacturers looked far other niches to fill with porro bins (like ultra0wides). But since it is very very difficult to make a roofer with an 11 degree FOV we lost the entire super and ultra wide bin group when manufacturers felt compelled to tell consumers that roofers are more expensive so they HAVE to be better, which is absolutely untrue.
ANY 7x50 non-ED roofer will look lousy compared to the Zeiss 7x50 Marine, and when Zeiss puts ED glass into the Marine then it will be better than any roofer 7x50 ever. If the new Habichts get the same multicoatings and ED glass as the roofers Swaro make, then the Habichts will produce a better image and be less expensive (and probably have a wider field of view).
So this sums up my recommendations of vintage bins, and why they make allot of sense. First of all, vintage porros are the only way to get a true 11 degree FOV bin or wider. Second, some of the multicoated Zeiss Jena 1Q MC models, Dokter porros, Jenoptiks, Habichts/SLCs and some others from the USSR and Japan are still nearly as good as anything else made today. And third the rush to roofers has made the cost of many vintage bins so low, they represent incredible values compared to new models.
I find my friends buying model after model of newer bins (95% roofers) and then becoming dissatisfied with them after a few months (or weeks) because they just aren't as sharp as their Nikon SEs or older vintage bins, and the new purchases are expensive. Roofer sellers promise everything and inexperienced buyers laud these new models to the skies on forums. But the real shock comes when my friends buy a 10x30 Kruger porro or an 8x30 Leupold porro that's so good for so little money. Then it becomes obvious that the real problem is this: people are hypnotized (for some reason, like retailer profits per item) by advertising whose logic is "Roofers are more expensive for a given magnification and objective than porros, SO roofers MUST be better." It's a shame this ruined the porro market, because porros are always going to be less expensive whenever a roofer and porro of similar quality are sold.