I am new to the class, and I don't understand Accelerate. Can anyone help me out? I am not sure, is it just like a better quicken? Where are the advantages? It tires me out, but other than that, I don't know.
The help file doesn't help me much.

You can put accelerate on top of metabolic quickening in order to go even faster. It does make a noticeable difference to your fighting.

However, it comes with the downside that you lose moves (if I recall correctly). Sometimes that's bad enough that you won't want to use it.

Everything Daurwyn said is correct. But once you get MU you will find that you can use it on top of metabolic quickening and not get worn out.

But you aren't going to be running someone down with it (probably).

I tried using it before MU and by the end of a fight (with a mob), I was out of moves. If you know you can end the fight quickly (and then turn it back off), then it's fine. But otherwise you're just asking for trouble.

Pks with lots of people, where basically it might make the difference between life and death if you get targeted. Admittedly my last transmuter was Hammond, from before dex changed and everyone could defensive spin. Maybe today it's not as important.