For me, the only "more popular" 1911A1 would be the Norinco if we were allowed new ones into the States.
Even if money was no object for me, I would take a Springfield Milspec anyday since new importation of Norincos is not allowed. Then again, if money was no object, I would own gobs of both brands! :biglaugh:
Others here in the thread have likely nailed what is actually most popular in general, IMHO.