Kevin, et al.
I've read so much here and elsewhere about the Canon 10X42Ls being only 10X37s, so I measured the diameter of both the exit pupils and objective lens on my own pair. My pair's exit pupils measure 4.2 mm horizontally (and slightly greater, 4.3mm and 4.4mm vertically), while the objective lenses indeed measure as 42mm. If there were some internal restrictions narrowing the effective objective diameter to 37mm, that would equate to an 8.8 power bino, and I'm quite certain, given the difference between my Nikon 8X32 SEs and my Canon's, that my Canon's are indeed 2X greater than my Nikons. Admittedly, however, I don't know how to measure the actual power of either.
Furthermore, when looking through the Canons from the objective lens, I see nothing but a perfectly round and unrestricted view; though I'm not sure what I should be looking for to see any restriction. Nonetheless, I think the measurements noted speak for themselves. My pair is new within the last 2 months, so it may be than Canon has addressed whatever was causing other samples exit pupils to measure in the 3.7 to 3.8mm range.
To address your second point, the warranty is short compared to a 25 year or lifetime warranty, but the 3 years Canon offers is longer than any other IS bino that I know of, with the possible exception of the Zeiss 20X60 at over $6K.
Thirdly, while they are somewhat heavy, I can actually hold them more steady without the IS engaged than any other 10X non-IS binocular I've tried. Of course, extended use is fatiguing, and I've found that using a monopod setup adds significant pleasure. I can leave the IS off and achieve an ever sharper image, though not by much.
Comparing these to Canon's 15X50s, well, there's simply no comparison. The 10X42Ls are brighter, clearer, sharper, show slightly better contrast, have less CA (almost non-existent), and the IS seems to work better. I've had three pairs of the 15X50s, and none of them were acceptable to me. Maybe that's just me, and maybe I got 3 defective pairs in a row, but they all went back. Perhaps if I hadn't already been spoiled by the 10X42s, I would have found the 15X50s to be far more acceptable, but I don't think so. I'm a stickler for image quality and resolution, and the 10X42Ls are the only Canon model I've yet experienced that satisfies.
My only caution on acquiring any of the Canon models would be to make sure the retailer has a liberal return policy. Sample to sample variation can make the difference between loving them and sending them back.
Dean