As this thread grows, it becomes blatantly apparent that personal taste is a very big reason to why some people prefer a big negative compared to a smaller one.
It seems that for some, 8x10 is the largest they will print from 35mm negatives, and simply don't like what they get beyond that. That is perfectly fine, and a representation of their tastes and feelings of what constitutes a fine print. I cannot argue with someone's opinion, because I don't believe that there are absolutes in this craft. There are good and bad ways of doing things, but no 'best'.
For me, though, the thread is not really about the ultimate picture quality regardless of format. It is more about how surprisingly good 35mm can be if applied correctly. And it's becoming obvious that to some that is less than others. It's all good. I'm so happy to find that so many people are still motivated by the 35mm format, and that it can be a real source of enjoyment.
I would strongly encourage those that haven't, go scoot back to my post #6 - (there was a url link here which no longer exists) - and read the hyperlinked article.
The hard numbers of resolution printed in that article is part of what tipped me over into trying 35mm 'for real', and give it a real benefit of my doubts about the format in general. In the months it took me to get deeper into the nooks and crannies of 35mm, I learned so much about myself and my abilities, and eventually I could see in my own prints what I didn't believe would be possible.
I have 9x12" prints from TMax 400 where I have to get my nose right up against the surface of the print to see any grain at all, where I see qualities in the finished print that looks confusingly like an enlargement from a 4x5 original. There are some small differences in how one tone of gray flows into another; it would be pointless to say that 35mm is equal to 4x5 in terms of quality, but it is shocking to me just how close it is in terms of final print quality, and that's the point I'm trying to get across. 35mm can be so good that the small gains in quality compared to 120 may simply not be justified, even 4x5 if you compare something like Tri-X sheets to 35mm TMax 100. What we do with that information is up to each of us to decide.
It may not even be the film format that helps us decide, it could well be what lenses are available to us. There is such a slew of lenses with interesting characteristics for sheet film shooters, for example. Old magic lantern lenses, for example, petzvals, soft focus lenses of all kinds, etc. For 35mm that selection would be different, and may well be a deciding factor in what we decide to shoot. For myself, I just like to continue using what I already have. My Pentax 35mm cameras are not exactly exotic. But they work just fine, and give me prints that many don't believe are from 35mm negatives. That's more than good enough, and I am so happy to have come to that point, because I love using 35mm cameras, both hand held and on a tripod.
I wonder if I am a total geek sometimes, and I should just go on making more pictures instead, and stop thinking so damned much about the process...
