For algo, Sierra Chart tops the list IMO. Others are CPU hogs and pretty sluggish. However, Quantower looks promising even though I haven't tried it yet. Their minimalistic UI is pretty appealing.
Some of the auto trading api platforms have a certification process for algos.
This means you cant go live on day 1.
You have to wait a few weeks for your algo to pass manual certification on their testing platform.
Basically this is the api platform provider checking you are a competent programmer and using their api correctly.
Some of the platforms wont have this process, because you are coding at a higher level, you can just go live whenever, im guessing with something like MT5 you can use it without any certification, because is it is a higher level platform.
IB dont require this step either, you just go live with your algo code which runs on top of TWS or Gateway from day 1.