+1 for the MTA group. Heard good stuff about them. That's who i'd do it with I was to do 1. They move you around to different workshops I think so you get a variety of work. (what I've been told)
But Mitch if your not sure what you want to do, just ask for a weeks work experience in whatever field you want, I know it's shit (no pay), but trust me it pays off! You might want to go into a certain field, but doing it for a week you see all the good and all the bad that's involved.
I had no idea what I was gonna do when I finished school, did work experience as a mechanic, cabinet maker, spraypainter and then electrician.
Then was hooked on becoming a sparky, commercial that is, none of this shitty crawling in roof crap, building new buildings. Finished my apprentiship last year with a big company. Earning good money (60k+) and if you work at a big company they dont make you work in the heat. When it hits 37 degrees we get to go home and get paid for the rest of the day, even if it hits it at 10am (happened plenty of times).
Anyway, but what I'm trying to say is, it also depends on what company you work for and who you work with. If you have idiots (to put it politely) that work with you it can make your life hell!
Well hope it all works out for you.
Sorry if I've talked alot of crap. Hope it helps tho.