If you can stand the weight pentalites of the ACR, here's what you get over the Tavor: (yes, I've owned both, and I now own two ACR's)
Better ergonomics than Tavor (about the only thing that ACR wins over the Tavor in this area is learning the reload. Tavor reloads are significantly different than the ACR) Nearly everything is at your finger tip (bolt release, safety, mag release) Tavor has safety at your finger/thumb. Mag and bolt release are built into the mag release, or a quick pull of the charging handle (the ACR does this as well)
Grips on both rifles are not interchangeable.
Both have forward charging handle
As mentioned, balance is different. ACR is tip/weight forward biased (similar to a full size Swiss Arms) the Tavor is more center balanced. You could hook your hand under the "carry grip" in the middle of the Tavor and it would be comfortable to carry it that way as it balances evenly. Overall, the Tavor weighs more than the ACR.
Accuracy is the difference. My ACR's shoot at 50m with ease and flat out to 100m with no adjustments needed (ok, minor adjustments to tighten the groups). The Tavor was less accurate and required adjustments/compensating for 100m
Size: the ACR feels smaller. It looks smaller as well. It's hard to explain this phenomenon, but it feels "small" when you hold it.
Driving from Target to Target: Not gonna lie here, Tavor manages this easily over the ACR. But that's just physics.
Trigger: ACR wins this round. You can adapt any AR trigger to the ACR by bending one leg of the spring. Giving you a vast array of variables and configurations. Tavor currently has.. Two?
Recoil: Both are very similar, I'd say the ACR is abit sharper, most likely due to overall weight?. I have installed Lantac Dragoon muzzle brakes on my ACR's and now feel nothing, so I would imagine it does the same to the Tavor. You get less muzzle rise with the ACR due to the forward weight.
That's about all I can think of off the top of my head, if I think of anything else, I'll post more.