It is a hugely interesting and rewarding career, if you have a passion for your subject and a love of inspiring young minds. Being totally honest, it is also very hard work, simply because every day is full on, and the expectations placed on you (not just by pupils and parents, but by Govt, Ofsted) are very wide ranging.
The training and NQT year will undoubtedly be the toughest part, and many people do give up (even if they've come out of other, quite full-on, careers). After that, it will get easier year on year, though whenever you change schools, it can be tough again for a couple of years.
I would say a typical day is probably, say, 9 hours in school. Most teachers will be in their classroom or office by 8am (apart from possibly part timers, on hourly rates) and will be there until 5pm. I would say the beginning of the day is more important - ie, if you need to work a short day, you're better off starting at 7.30/8 am and leaving by 4 pm rather than trying to dash in at 8.30 and playing catch up all day. Of course you'll have meetings/ parents evenings etc on top of that, and in your early years of teaching, perhaps two hours marking and prep per evening, and then an afternoon/day at the weekend. I've found that over time, I'm able to organise my time so that I bring less work home - though having said that, I do a longer day in school, aiming to start at 7.45 am at the latest.
The paperwork is immense, and can get you down at times. Govt changes can also be frustrating. And of course you have to get used to the idiots who think your job is 9 til 3... lol
If you're in a shortage subject, then its well worth considering, though its hard to get into popular subjects these days.
Overall, I can't think of a more worthwhile or fulfilling career, and you'll meet many likeminded, interesting colleagues.
Good luck with your decision!