Been mountain biking for about 3 years now, and i worked at a bike shop for almost a year. First things first,
1. Know the frame size you want, your height is taken into consideration here as well as personal preference. Frames are a crucial part of a bike, its structure, your foundation. Frames are made out of many different things these days, and wieght should also be looked at. Both of these play a very large part in over all comfort while riding.
2. What kind of riding will you be doing most of the time? While Full suspension bikes are bundles of fun and can take a very intense beating, there not for everyone, and generally speaking if your going to be doing more XC/easier riding its not essential.
3. Components, make sure they are decent quality, these are the things that will dent your wallet later on down the road. Brakes, and derailluers are the big 2 here. When looking at brakes dont look at what "looks cool" especially if your actually going to be riding this thing off road and in hazardous situations. Just because there is a disc doesn't mean its good. While working in the bike shop I encountered way to many cases of "My bike wont shift", and "My brakes dont work". While most of these can be fixed easily with re-adjusting, its money you don't need to be wasting, and you will most likley need to be coming back a few months later. Most important thing to remember here (and with alot) is the more money you spend, the better bike your going to get. Other things like tires, wheels, spokes, pedals, levers, shifters, and handle bars are also very important, and are often the source of failure.
I'm not going to lie, i have gone through 4 bikes in 3 years. Now I worked in a bike shop, and therefor didnt have to pay for alot of what i rode (and broke ( : ). The most exspensive bike I have owned is the one i am currently riding. It cost me a total of about 1000 (Had i not worked at the shop it would have been about 2000). However not the nicest bike, I have had the luxury of riding a Surly karate monkey that was completely decked out, unfortunently i couldnt bring that when i moved : (.
All in all I would strongly suggest that you "test" some bikes out before buying. Go to a local bike shop and talk to them about what kind of riding/price range and they should point you in the right direction. Also point out to them your level of skill, because yes the fact is some bikes are literally "harder" to ride then others. In your case the bike your looking at is an entry level mountain bike, now if that is your level of skill then by all means that might be something for you. Be aware that bikes are not cheap, and they will only continue to get more expensive. Hopefully this post will help you, and dont forget to SHOP AROUND, its always nice to look around at different brands, and models. Good luck in your search, and regardless of what you end up getting HAVE FUN RIDING IT!