I have always been torn between a 5A or a 5B stick. The extra bit of power I can get from a 5B is great, but they have always been just a little too big for me to feel comfortable.
The 55A provides that extra bit of power when I need it, without feeling too foreign or awkward.
As with the majority of Vic Firth products, they're consistent, and pretty durable for the money. I playing can be on the heavier side, and the sticks take a fair bit of abuse. Definitely worth the money.