I've built many in both 1/35 and 1/72 scale. The only Abrams kits I have not built yet, but I do have them is the 1/35 Trumpeter kit (M1A2), 1/35 Italeri M1A2 and the 1/72 Revell of Germany M1A1HA. I use the Trumpeter kit for detail parts, I had the Academy M1A1, but gave it to my 13 year old son since I did not think it was worth building with better Abrams kits so plentiful.
In 1/35 scale I've built several of the Tamiya original M1 Abrams, both motorized and static, both of their M1A1s, DML's M1A1 and M1A2, Esci/AMT/Ertl M1 and M1A1. Most of these were built OOB before I discovered accurizing, scratchbuilding and aftermarket accessories. The DML M1A1 is the only one I've actually used any aftermarket on and I built it about 6 years ago. This was the last time I built a normal scale Abrams kit. The Esci kits were built when the only other Abrams kit on the market was the original Tamiya kit, around the 1988-89 time frame.
In 1/72 scale I've built the Esci M1 and M1A1, Hasegawa's M1 and M1E1 and Matchbox's M1. Again, these were built OOB many (15) years ago. The Italeri M1 is the first small scale one I attempted to accurize. It was built late last year.
I do have several 1/48 scale M1A1 and M1A2 model kits. These were all designed to be motorized and not serious Abrams kits. I haven't built any of them though.