(copied from my review on it on Pinkbike)
I bought this bike back in 2005 to be able to go riding with some of my friends who were already in the sport (a few weeks before that day I'd totally messed up my Walmart bike). I went into my LBS and after a lot of thinking whether to get the 15" size or the 17" I got the 15" thinking that it'll be better suited to my riding style and it'll be flickable. Oh boy was I right! I absolutely loved the bike, especially the frame, from the second I got it. The components are OK to start off on but really you should be looking to save up money and get ready to change what brakes. The frame, with a decent build, is a good all round beginner's bike as it's good for street and just fooling around with it, DJ and even some freeride/downhill for those of us who can't buy a new and better bike.
Since March I've put this bike through hell, I've used it for lots of downhilling and trail riding aswell as the occasional urban ride & freeriding and it's holding up great. The components I had to replace were the pedals (very weak spindle and middle part made of plastic, very prone to failure) and the crankset (slightly weak, bashguard reccomended). Since then I've upgraded the drivetrain, the wheelset and the brakes but those are more for the sake of upgrading rather than swapping it ****ty components.
In June I actually hit up a bikepark with this bike (Vallnord Bikepark, Andorra) and although it wasn't suited for this type of riding it help up very well (careful with the pedals and crankset though).
The bike isn't heavy at all and the wheelset actually stands up to a surprising amount of abuse as long as the rider isn't too heavy. One of my favourite components on it, aside from the frame, are the Specialized Enduro Sport 2.2" tires, they're great for all types of riding, they've got good grip and they're cheap (15 euros each).
Pros
Beefy frame
Fairly good componentry to start off with
Good allrounder
Cons
Non disc-compatible wheelset
Integrated shifter & brake lever, i.e. when you upgrade to discs you must change shifters too
Acera rear derailleur, isn't exactly good quality although it does hold up fine
Frame disc tabs are weak and got bent slightly (needed facing) or came defective, I do not know
Don't be put off by the lengthy list of cons, the pros far outweigh the cons in my opinion.
Overall, I'd have to give this bike a 8.5/10, excellent bike for what you pay and if you wish you may upgrade it into a very nice hardtail (like what I'm doing, I can't afford a fully, hell, not even a new fork ).
Ideally you'll want to upgrade to a better frame sooner or later but I definately think it's worth upgrading the Hardrock frame as it is a great starter bike.