Would not know about those and either Extender my self.
My Eagle Optics one performed well enough with my 8xSE, that I decided to "upgrade" to the Elite one.
On the 8x SE, fits on the occular's eyecup well, and it makes a very nice combo. Image reminds me of a good early 90's spotter.
Something i failed to mention before, is the close focus performance. A few months back, I used this combo when out hiking without my pair of Papilios. Close focus was a tad over the view naked eye from 4 inches away. It was also of good quality.
Other binos I have tried it with, and had good results:
12x SE (the shallow focus complicates it a tad. To avoid noticable CA with the 12x when it is boosted, focus has to be spot on.)
Swift 8.5x44 ED
Leupold 8x32 GR HD (Optically speaking, but the problem is the eyecup being to wide for the Extender. The bino has a huge eye lense.)
But the best results are with my 8x SE, which, kinda figures :t:
Have not tried it with my alphas of yester-year, but i do remember the Eagle Optics one working well with the 7x42 Zeiss Classic, optically, though it could not fit on without being held on.