Viper is still a good option, if I don't like the Opticrons for some reason, I may fall back to the Viper 8x42.Im sorry the Viper didn't work for you. I think someone pointed this already whether here or in another thread, but I also find 10x is a "speciality" binocular (and compared to 10x42, probably 10x50 is even more of a niche binocular, that's why I find these very 10x42-ish and hence interesting). I use mine on particular opportunities: long range, coast, waders across a pond, etc. In these occasions I find they can offer something (although 10x is no miracle; I remember the first time I looked through a 10x I was frankly underwhelmed by the magnification), but for an everyday binocular I find 8x (or even 7x) much better suited. I think 10x over long range is more comfortable, because you don't have to concentrate that much to pull out detail, but I'm not sure how much detail is not actually there at 8x, probably 99,9 % of the detail is there, but with birds far away you have to concentrate to "extract it" (if you know what I mean). So in my opinion and experience 10x are more suited for that kind of birding not because they discover something unseen, but because they do so in a more comfortable way. Reversely, when I carry my 6º - 10x binoculars and I'm following passerines I really miss my >8º - 8x binoculars, first for the FOV (easy to locate birds) and then for depth of field (focusing is not as critical) and finally for stable view.
I'm sure you'll enjoy the new Opticron, wether 8x or 10x. However, there's a lot to say about inexpensive but nice binoculars, like your Adventurer's (or the Kowa YF and the like). They offer so much, that when buying optics 2x, 5x, 10x more expensive you have to marvel at the great deal they represent.