I've had braces for 11 years now, and still have another 6months - year left. I've had all types of retainers as well as braces so you could say I'm an old hand at living with them
I had some serious overcrowding as well as severe underbite. I had braces/retainers for the first 9-10 years as a precursor to surgery (they actually changed the procedure they were going to perform which is one of the reasons I've had braces so long), and I'm just on the last round of orthodontics.
As you might guess I've had braces through Secondary, College and University and to be honest I don't think I was ever treated differently because of them.
Braces (or traintracks/brackets) as many people have already mentioned can be very painful for around a week after they are first put on/after they're tightened. Over the 10 years I've found that after going to get my braces tightened sometimes it would be barely noticeable, whereas other times I couldn't eat for days - it really depends on what your orthodontist is doing, what wires and elastics etc they end up using.
They're not that bad to live with, although you will find food getting caught up in them, and you may find that they rub a little or the end of the wire sometimes pokes into your cheek - just get some orthodontic wax to cushion it.
Retainers are slightly easier to live with as you can obviously take them out

. They do however hinder speech a little, but you get used to it after a few weeks/months.
I've got perfect teeth now and have to say that I'd make the same decision every time!