Well, it was a much anticipated kit that was going to make the 30+ year old Tamiya M3 obsolete, but it didn't quite hit the mark. Some areas are vastly improved, like the option of vinyl or single link tracks and the interior. Plus the old Tamiya kit was a diesel engined variant that never left the states or saw combat.
At least the interior for this kit is correct. Academy used the same interior for the M3 and M3A1. The interior provided is for the M3A1.
Overall it is a nice kit to build. It fits well and has good details. A bit of the detail is wrong. I think the rear hull overhang is a main point of issue. The kit depicts an angular riveted rear overhang, but the tank had a curved overhang.
Make sure you check out this site for pointers as well as the photo link at the bottom of that page. I linked this rear overhang photo from that site: http://usarmymodels.com/MANUFACTURERS/Academy/academy1398.html