Can anyone explain the differences here or the pros and cons of each for me? I'm new to the sport. Thanks.
I'd have to say hardtails is generally used for cross-country riding while full suspension is used for downhill and now adventure racing. This, to my understanding, is due to the physics behind the design. A hardtail will be more efficient for flatter terrain and in hill climbing because of the weight of the components. Full suspension tend to weigh more plus, the shock absorption on the rear suspension of a full suspension bike makes hill-climbing more difficult because energy is actually lost through the shock dampening. I guess the reason full suspension is used in adventure racing is the rider spends so much time in the saddle, they need the relief the rear shock provides. I know this could probably be explained more easily than I put it, but did this help? Let me know if there is anything you'd like me to try and clarify. Cheers!
The main difference is a few thousand dollars. It's not worth it to buy a cheap full suspension for a variety of reasons. Extra weight, less efficient, and not very durable.
In general, though, hard tails are lighter and are for very flat riding. If you're going out once every few weeks a hard tail should do fine. The primary benefit of a hard tail is that they are lighter and so on climbs it takes a little less muscle. However, on technical climbs they have a tendancy to bounce around & on descents they beat you up.
Full suspensions, however, come in many styles. Cross country (the lightest of the bikes with 3-4" of travel), all mountain (In the middle of weight ranges and 4-5" of travel), and downhill (heavy bikes with 5"+ of travel). So depending upon the style of ridng you're planning on doing you should get a bike for that. If you are going to be going out three to four times a week, then I would go with a full-suspension. You can handle a more variety of terrain and you wont get beat up as much.
I have both a hard-tail & a full suspension (x-country flavor). I am a much faster rider on my full suspension, both up & down the mountain . I have lost some bike handling skills since I've got a full suspension though. Thats why I use my hardtail for some of my training rides. I usually ride my full suspension but depending on the event I will use my hard tail. For 24 hour races and most x-country mtb races I use my full-suspension, but for the occasional hill climb on fire roads I'll break out my hard-tail.
If you're just getting into mtn biking now is a good time to go to the local bike shop (LBS) & start looking. Most LBS's are putting their '07 stock on sale & are getting ready for '08 gear.
I know this post is a bit old, but I just published an article from VeloNews: Which Is Faster: Hardtail or Full-Suspension?
That might help those of you still debating whether to buy one bike or the other.