Shields are very unbalanced. Faster charge beats the shtako out of bigger shield.
Currently shields in this game seem incredibly unbalanced. The second I got my first 3 second recharge shield I've never looked back, because it's simply superior in every way to slow charging models that tend to only have a small increase in shield capacity.
The fastest charging shield I found has a 2.85 second activation, 40% recharge, and 1030 shield.
The slowest charging shield I found has 12 seconds activation, 10% charge and 1560 shield.
The fast shield has four times better activation time, four times better charge speed, and only about 30% less maximum shield. That just seems incredibly lopsided to me.
Granted, there is the additional consideration of BMGs, which can recharge a slow shield just as well as a fast shield, so if the shields don't have to charge at all that's a minor advantage, but the reality is, finding a 5.5 second break in the action to recharge a fast shield is a thousand times easier than finding a 22 second break in the action to recharge a slow shield, a measely 500 more hitpoints just don't make up for that kind of difference.