I just finished building the Academy and Tamiya M1A1 kits from the 1990s. These models are for adding to our club's display cases in the local VA hospital here in Grand Junction.
Anyway, about the 2 kits: Avoid the Academy kit. Inexpensive and there's a good reason--it's very inaccurate, plus it doesn't assemble well. The Tamiya kit builds fine, but it is also a bit inaccurate. I bought both kits on eBay for a fraction of what more current Abrams kits sell for, so there's a trade-off. I needed many 'Nam & sandbox models, as that's what the vets asked for, so I sought out some cheap stuff on ebay. You get what you pay for.
If I were building an Abrams for my own collection, I would definitely want a more current model that better represents what was/is being used in the sandbox.