The Yak-3 has short legs and a light armament with very limited ammunition. It's not the fastest ride around either. If you perk the Yak-3 then you'd have to perk a whole lot of other stuff (K4, D9, 51D, 47M etc).
I've never had an issue in dealing with Yak-3s. IMHO the 9U is a superior ride, and the 9T is better for base defense in that it can deal with armour (I managed to pop my first T-34 turret last night, made 1hurless very grumpy)