To resurrect an old thread...
I've shot the TRG42 (338), AI-AWM300, and I own an AI-AWP (308). I've handled but not shot the Tubb rifle. (And of course I have experience with conventional Rem700's and Win70's.)
The AW/AWM/ASM series has a "field replaceable" barrel system, and the parts are made such that you can take a bolt from any other same model drop it right in. Of the TRG and the AI, both will shoot half-minute or better from the box with no load development. The consensus on SH and SP.com is that the AI is a "tougher" rifle which will put up with more abuse. The bolt seems to run more "on its own" on the AI vs. the TRG (for me).
If I were to buy a 338 or 300, my choice would be the AI-AWM. It's probably the most well thought out field-worthy precision rifle.
Comparing the Tubb to either the AI or the TRG isn't really appropriate. The Tubb is an extremely focused design for shooting from defined positions, not for humping all day across the Wyoming or NM high plains and engaging targets from improvised positions. That super adjustable Tubb stock just doesn't work very well shooting from weak-shoulder, for example. Is a 25oz Anschutz trigger reliable when the rifle is caked with sand dust?
In response to Steve's question, "Why aren't the top competitors using it?" -- They are, but you're looking at a different game. The AI's win or fare well (depending on the shooter) in IPSC/USPSA "MOR" (manually operated rifle) class and in the "sniper/tactical" or "practical precision rifle" matches.
$4k price hike? Let's say we're comparing a $4500 AW to a $800 Rem PSS. With the AW, you get a superior action permanently bonded to the frame substructure, fully adjustable stock ergos, field replacable parts & bbl, optics rail machined into receiver (albiet the AI rail), a great adjustable 2-stage trigger, a magazine system that actually works when dirty, and a whole sytem that will shoot half MOA or better with basically any match quality ammunition. You can forget finding the load your rifle "likes" and doing painstaking load development, just pick any decent match ammo.
Yes, a $3000 GAP gets you real close, but you're still "stuck" with the limitations of the Rem700 action.
Of course, this may be a moot point if AI's post-buyout management makes drastic changes.
-z