I'm assuming that you're asking about Eric Young's Squad Assault, the remake of GI Combat.
I prefer CM. It is similar to CM only in that it is a 3-D WWII game. LOS is difficult to determine. Initial placement of units is imprecise. These two things make (for me at least) AT guns almost unusable. Tanks are difficult to control, they can't be used for much other than infantry support. (Though, given the scale of the game, this is probably okay.) The infantry do seem to be modelled with less abstraction than they are in CM. It is primarily a company level infantry game.
It is a big improvement over GIC, which was an abomination. SA is at least playable. And Matrix seems to be committed to giving the game decent support, something that GIC never had.
In my experience with the game I'd say that if you're a nit-picking detail obsessed control freak
you'll hate it, but if you'd like to watch cool pictures of army-men run around and get splatted on your computer screen, then it's kinda fun.