I am slowly switching from mountain to road. I stared with a GF hard tail in 2009 and then got into racing mountain bikes. The thing is, it is expensive to maintain a mountain bike. I have had an entire drivetrain go in in 500 miles whereas a road drivetrain can last 5000. Also, when the trails are muddy you can't ride. So I started training more on the road and this year I did my first road race. Had fun and made all the innocent cat 5 mistakes (pulling, early sprinting etc).

I don't know that I will switch to road racing as it is a sprinters sport (well at least the local crits are), but I am certainly going to ride road more.