I do not see me getting totally into MTB, as in place of road riding. That is not to say that I will not enjoy the MTB and will not do a good amount of it, but I doubt it will take the place of riding as my favorite as far as cycling (running is my favorite activity). Part of the reason is my location. Indy has very little in the way of trails. There are two main trails in Indy that are like 3 and 7 miles long. I have already looped them a few times. Yes, I can get to the point where I will get much faster and better at them, but still I cannot see myself going every week or more than once a week. Yes, I could travel to some surrounding areas, but that is not going to happen often as I have two young kids and I already spend a lot of time working out (swim bike run at least 2x per week) and away from my family. Taking a 2 hour road trip to ride is just not going to be common for me.
The second part is conditioning. I love road cycling as a break from running as I can get a very steady workout of like 4 hours. I am into endurance stuff more than short stuff . . . Riding 4 hours around the same loop might drive one insane.
It will take some time to fully realize that the bike is not the flower that a roadie is. It has already happened some and will continue to do so . . . I just hope the opposite does not happen: thinking I can take anything on my roadie.
That all said, I am pumped about having a MTB and look forward to doing it more. It is a ton of fun and I will only get a lot better on it. I doubt I will ever get a FS and get into free riding or downhill, just by nature I am a tentative person. I am not the one to go balls out down a hill without trying it real slow many times before. I am not exactly a coward - I hit these relatively easy trails with a good amount of speed, just not what I know some others would do.