Just got into mountain biking this summer and have been loving it. Purchased a 2013 Specialized Hardrock in July and have probably put around 200 miles on it so far.
Been a blast but have already had to "upgrade" a few things due to me breaking stuff. New rear DR after a stick busted the schit out of mine, new set of cranks after pedal threads completely stripped on the cheap stock suntour ones. Both lead to fun hikes out of the woods for me.
Now I want to put a real front fork on it.. and replace my wheels/tires. I see why so many people suggest holding out until you are willing to spend $$ on a level or two above an entry level bike. On the high end have done a few 15 mile rides, looking to push it to 20 soon. Definitely not a cheap sport!
Getting pretty good with a lot of the climbs in my local parks but haven't ridden the tougher park around here yet.. may try and hit it up this saturday if weather holds.