Generally speaking, and this is not true for everyone but is just an observation; the best riders that I see, the fastest and the strongest and usually with the most skills, they choose to ride hardtails. With a hardtail, you get a true feel of the trail, the bike does not waste any energy and the rear of the bike is where its supposed to be all the time. This can be hard to imagine what I'm saying, but the bike will track better as it moves through ups and downs, obstacles, downhills and jumps. Any rear suspensin, no matter how much it is, 1/2 inch to 8 inches, all it does is make it easier for the rider to accommodate the conditions. If you don't have the skills or the energy or the desire to be jostled, jolted and jammed while riding the hardtail, the suspension will soften and make easier, the ride for you. Look at how big the BMX riders go. They go frickin huge! No suspension at all. If you are doing mostly big drops and riding man made structure, it makes sense to have a big hit bike. If you are doing any of the jumps or structure on the trails, you really do not need it. You may want it, but you don't need it. If you are a large or heavy rider, then it could be different because the big hit bikes are just about the only bikes that can handle the forces a big rider is going to put on the bike. Until you get back to the hardtails, as these bikes are strong. However, how many riders can put the effort into and take the beating that riding a hardtail gives you.
I have three bikes that I have accumulated from riding the past ten years. A single speed that I seldom ride, a road bike that I just got and love it ( mostly because it is great training to be a stronger rider ) and the third bike is a HANDCRAFTED AMERICAN MADE 4" full suspension cross country bike that has a lifetime waranty on the frame. I graduated to this bike after having several cheaper bikes the previous years and because I like to ride so much. Saving and spending the money on a bike like this is a worthwhile investment. The money spent for quality products is an investment in myself on what is really the only hobby that I have. You won't see me dropping 200 bucks at a golf course or spending big to go out boating. Having all these bikes doesn't make me a yuppie, or even wealthy. From being in the sport for so long, you accumulate things. Keep riding and i'm sure you will have a stable of ponies too. I am anything but a yuppie, but if I was, would I not be accepted? As Seinfeld said in one his episodes, "not that there is anything wrong with that" . Grin Out on the trails, we are all riders. I am finding out from riding the road, the roadies are cyclists just like the mtbers. Alot more in common than I would have imagined. So whatever the reason is that a cross country bike won't last a day for you, that problem can be overcome. Whether you have to become a stronger rider, or increase your skills so as to be able to land properly once you get airborne, you can lighten your load from that heavy 40 pounder big hit monster. Grin