I rather like the STI but last I heard the waiting list was out 12 months and that was for the solitary configuration it was available in (5.5" barrel, 45 Colt) - this makes it difficult to offer up much in the way of a ringing endorsement.
Nevertheless, it has the most agreeable action of any single action I've tried (not like I'm an expert in such matters) but it does make my Turnbull Classic's (USFA) trigger (and action generally) seem like 18 miles of bad road by comparison.
It costs more than a new Colt and that provides some entertainment as reports of its purchase will amuse some, irritate others and astonish the rest. I'm not totally clear on why - it's actually something of a bargain given that either the Colt or a higher-end USFA would cost more than the STI after the costs to tune the thing were added in - I daresay a simple spring swap would not get you into the STI's neighborhood.
As for USFA, it is kind of hard for me to pay more for a replica than the real thing.
While this is not an uncommon sentiment I've sometimes wondered why one seldom hears similar comments in relation to the Colt 1911 - the proverbial woods are full of 1911s that sell for more than Colt - Baer, Brown, Nighthawk, selected STI and SA and others. What is it about the revolver that's more sacrosanct than the auto? One of those mysteries I'll simply have to live with, I suppose.
As far as SAA-alikes costing more than Colt's, I believe Turnbull has STI beat and has way more variations available.
http://www.turnbullrestoration.com/store.asp?pid=27608
FA is great stuff but throw Turnbull into the mix if you're looking for something special. I wouldn't have the patience to go through the STI ordeal a second time - shoulda bought a pair when I started.