I had an N scale layout where I mixed Atlas & Peco flex track (code 80). After the ties and rail sides were painted, and the track was ballasted (Woodland Scenics brown ballast), from 3 feet away I couldn't tell which was Atlas and which was Peco. Is this really a big deal visually, or is it something people obsess about because they *know* about it?
If you know what prototype track looks like, the difference between that and Peco (or Atlas Code 80, which also isn't very prototypical in look) is pretty obvious, particularly in photos where the track is prominent. But I suspect a lot of people would be hard-pressed to identify Peco track as "non-prototypical" for NA if all they saw was properly painted/ballasted Peco track.
Some folks are obsessed about prototypical accuracy. Well, maybe more than "some" - it's why we have RTR models these days that stress that: rolling stock, engines, cabooses are all judged on minute differences from the prototype among the congnoscenti. But if what you want is bullet-proof track that just works, it's hard to beat Peco. I've had Peco switches on three N-track 6' yard modules that I built back in 1995, and they are still going strong despite the abuse that modules get in setup/tear-down/transportation. In fact, all NEW modules for our Ntrak layout now use Peco Code 55 flex and Peco switches because this combo is virtually indestructible and just works.
I used Peco track and switches on two early layouts I built. When I built my current layout (my 3d, and last, effort), I went with Atlas Code 55 because of its more prototypical look. But there are many days when I wish I'd just stuck with Peco Code 55 flex and Peco turnouts. Photos of my layout look pretty good, but I care more about operation than photos. Atlas code 55 track is simply not very robust, although I can't say I've had any really serious problems with it over the past 15 years. The turnouts are the weakest link, with several having gauge issues and a couple (out of 90 or so) that had to be replaced, and I'd use hand-laid turnouts if I had to do it all again. But I suspect that if I'd just stuck with Peco, I'd be just as happy, if not happier, with the operational consistency.
John C.