I think there were 4 different Merckx ti frames. I have an early AX with 1 inch steerer tube, no welded-on cable adjusters, and no separate seatpost collar clamp (
http://forums.thepaceline.net/showth...ghlight=humbug ). I think it's a great neutral bike. Agree with Saab that it's no Look 585, but a very capable bike, nonetheless. Especially on crappier roads and longer rides.
Other Merckx ti frames were the EX, Millenium (made of 6-4 ti, very shaped tubes), and the Majestic, which I consider a second generation AX - with 1-1/8 steerer tube, welded-on cable adjusters, and a seatpost collar. I wonder if something was lost, though, going to the Majestic from the AX...