I did one in Design Technology. It sent me absolutely insane. I finished it, went to Glastonbury and then walked back into my old job the day after and haven't regretted it once.
Started drinking loads, lost my fitness, long term GF and my social life was none existent! My tutor said that isn't uncommon either. Unless your doing the classic subjects or PE forget teaching anything that is related to fully understanding the subject, that advert where she makes a wind tunnel makes me laugh out loud everytime.
Its certainly not a safe job either, there are people off my course who still don't have jobs a couple of years down the line and their PGCE's are invalid after 5years.
But if I haven't put you off Its a great way to move overseas. I did get to try some private schools as well as some comps and overall i'd say the comprehensive is more interesting and much more rewarding but for me I felt like I was qualified in babysitting.
Get a taster first you really have to be into it to enjoy it.