I think the overload is more to do with $$.
I like transformers. The more the better. Either they work or they don't...there's less shit to tinker with.
RE: API trafos, you typically can't use API type trafos with neve outputs because of the DC at the output. You generally need gapped outputs, and usually larger core 3/4" vs 5/8" (except the mini 1166 by ed anderson which is 5/8). You can get Ed's neve trafos at hairball audio, or you could try to wind your own if you can get lams where you live.
Another option is buying the chinese trafos people take out of chameleon labs preamps when they "upgrade" to Carnhill. Saw some inputs on ebay recently for $10, outputs were something like $5. Doesn't get cheaper than that. People will say that they are chinese and therefore suck, but that's just gearslutz talk.
My chinese 1084 preamp (chance group buy) sounds just fine with it's chinese trafos (once you correct the zobel networks, shield the toroid, and swap a few caps), and the only person who has done a carnhill trafo upgrade on these and tested both (that I trust anyway) is Rodabod. IIRC his words were that the difference was subtle. (EDIT: my memory is obviously lacking, so I posted his original post below). Maybe I'll do the test also, but I'm lazy, and I am thankful that he did it for me. So anyway, yeah I guess I'll get flamed now.
(Roddy's comments on the chineVe vs Carnhill trafos)
[quote author=rodabod]Basically, the Carnhills seemed to have a slightly thicker bottom-end and low mids, whereas the Chinese models either sounded harder or thinner (maybe they were just cleaner, who knows?).[/quote]