Well most of what's been said here is true. I've played rugby for 4 years, and have had: torn quadricep, torn calf, broken ribs, fractured fingers, dislocated shoulders, various concussions, countless sprains, and too many scrapes, bumps, and bruises to even mention here.
That being said, I think it is the greatest team sport in the world. If you're lucky, it may not affect your training, and it will give you some great conditioning benefits, as well as a fun time. If you're unlucky... well, I couldn't torque my shoulder into a squat position or do any kind of heavy pressing for about 6 weeks after I dislocated my shoulder.
Bottom line is that I think it's a great time, but don't put it on the same level as going for a sunday jog. Rugby is a very physically demanding sport and has the potential for injury.