Not unwatchable but not very rewatchable either, IMO.
I honestly appreciated how they tried to mix elements of the first 2 films together, but it's easy to see why some things got lost in the shuffle.
Action isn't very thrilling (but at least it's serviceable) for the most part except in the climax when John Connor lets loose on Arnold. Now that part I liked.
Arnold as expected is great as the Terminator. The rest of the cast except Simmons were pretty much just there.
6/10 I guess?