Yes, it's a great experience, very rewarding and you meet some great people. I've been instructing for over 3 years, PPL, IMC ratings and night. The night and IMC is great fun, you do get a bit tired of straight and level after a while.
Students vary massively, some are the best people you will ever meet, some you would never want to see again when they step out of the aircraft. On the whole, it's well worth it for the life experience.
but...
It's a difficult lifestyle to keep. You never really know how much money you're going to make each month, so if a big bill comes your way it can wipe you out. If you can get a salary positions, you must be some kind of god.
It can be very frustrating when you sit at the club all week when the weather is pants, and on the day off when it's good weather and you're meant to be enjoying a day with the family you feel bitter because you could be flying and earning money.
In certain clubs there can be a lot of rivalry for who gets the most hours each month, and if you're on the wrong side of the ops girl you can find you don't get allocated much at all.
It would be very difficult to make a career as a PPL instructor these days, which was my original intention, you would have to move on to CPL or IR instruction to earn a wage. Everyone says money isn't important if you're living the dream, but you have to at least get by.
I would recommend instructing to anyone who really wants to pass on their knowledge. If you're just looking to build hours I think you would be wasting the students time and there are enough people doing that already.