Lots of choices out there. Tamiya's new M1A1/A2 OIF kit is the easiest to build and the newest tooled. Not necessarily the best. They all have their goods and bads. Here is a rundown of most of the available kits
Tamiya's lacks the prominant anti-slip coating. It does come with a nice USMC MCD, APU, and some modern stowage and two descent figures.
Dragon's is a close second to Tamiya. It is a little harder to build, but does have the anti-slip coating. All of Dragon's M1A1/A2s also come with a partial interior. The newest Dragon USMC M1A1HC Baghdad kit also comes with a nice selection of gear, MRE boxes, and PE for the Bustle Rack Extension (BRE), however, the BRE is a US Army 3ID type, not USMC type. Dragon has also announced an all new tooled M1A1AIM to be out this fall. The M1A1 AIM will share most of its componenets with their recently released M1 Panther II mine clearing vehicle. Many improvements have been indicated over the Panther II as well.
http://www.perthmilitarymodelling.com/reviews/vehicles/dragon/dr3534.htmTrumpeter is about on par with Dragon. It has the mud relief holes in the rear sprockets, one of only two kits to have these. It also comes with some extra ammo boxes and gear.
Academy's is horrible. It has a sprue with some updated parts that are great for OIF, such as USMC Bustle Rack Extension, new style sprockets with mud relief holes, smoke grenades for launchers, USMC MCD, nice APU, etc. Other than the new items, it is the same old bad Academy kit with short M1 turret and old style T-156 tracks that haven't been used since the early 1990s.
Italeris is an improved copy of the Trumpeter M1A1HC.
Here is a side-by-side review of most M1 Abrams kits out there.
http://vodnik2.republika.pl/pages/m1-comparison/m1comp1.htmReview of new Tamiya M1A1/A2 OIF kit:
http://www.perthmilitarymodelling.com/reviews/vehicles/tamiya/tam35269.htmReview of new Academy M1A1 Iraq, 2003 kit:
http://www.perthmilitarymodelling.com/reviews/vehicles/academy/acd13202.htmReview of Dragon M1A1 USMC Bahgdad 2003 kit:
http://www.perthmilitarymodelling.com/reviews/vehicles/dragon/dr3533.htmEDIT: Guess we were all posting about the ame time. There should be plenty of info above for an informed decision. Good Luck.