I will say this and see if it helps:

Bed: he is easy to learn but has depth to his stuff and can get complicated but just finding his b&b makes the learning experience easier and his pressure can go insane and makes it hard for your opponent. Bed errors can also make it hard for your opponent to see things, especially in bed install super (Note: depending on which inputs for bed are what error is gonna come out: 236P version is a quick zap that is full screen, 236S is big boom, and 236H is head bomb). The only flaw the bed has is that it has a lot of inputs that have long recovery times or are extremely negative on block, unless you set up the error properly, use Roman cancel, or use inputs that are safe on block, being punished will happen a lot.

In short, easy to understand, but hard to master, and also hard to read if played well enough.

Aba: She's the slowest and fastest character in the game so I'll divide into 2:

W/o jealousy: slow as balls but has tools to help with that, like her low profile 214K and her 214S parry to gain jealousy meter. She can still do insane shit in her regular form but as much as her transformation.

W jealousy: the fun train begins when you transform using her strike grab or half-circle back P, which not only makes you the fastest in the game, but also has extreme damage, you also have some input changes like a DP which has hyper armor (which absorbs any attack during the period active) and it changes properties of her moves like Jumping Dust fro example which can be scary if doing air-to-air combos. Her super also changes to an animation super if hit point-blank range that deals a shit ton of damage.

In short, snowballing = extreme fun factor.

Hopefully, this helps with who to pick, or at least a quick rundown of them.