Here's the deal for me. If you're relatively new, and you're not doing massive drops, if you're not doing burly stuff that absolutely requires a full suspension, look at a hardtail. More particularly, look at a steel hardtail. I know you're looking at really cool suspension bikes, and it's easy to get swept away with OOO, AHHH. Compared to a hybrid city cruiser, even just moving to a hardtail with a real shock on it will be a big switch. The frame geometry is a little different, and the shocks are (hopefully) made differently, that is to say stronger, with different dampening characteristics for the bumpier terrain.
I know, I know. Full suspension bikes are supposed to be the sh?t and all. And aluminum frames are supposed to be superior. They are stiffer and stronger by weight... but don't let that fool you. Machining costs are a lot lower, too, so don't get sucked into thinking that they're so widely made because of the riding characteristics. There's a reason Trek doesn't make steel hybrids anymore.
But here's the thing for me. I have aluminum, I have steel. Yes, some steel frames are a little bit heavier. I don't mind it, I'm a heavier rider, and if the frame is a pound or 3 more than an aluminum frame, my own weight fluctuates more than that on a weekly basis, I'm sure. That said, some steel frames that cost less than that suspension frame will be roughly about the weight of an aluminum bike. Steel is springier than aluminum. It'll flex a little bit more on those small drops, and it doesnt' develop fatigue over time like aluminum will. (Granted, aluminum frames have by and large been pretty good about that, but still) So it won't be as cushy as those FS bikes, but I've felt the confident flex of a steel frame as it soaks up smaller drops, and takes up the bumps. A good set of tires will help, too.
FInd someone who will let you try a "real" mountian bike on the trails. The more different bikes you try the better.
Try an aluminum hardtail. Yes, it'll be stiff, you still might like it. Get a feel for it. Then try a steel frame. To me, there's just a little bit more that the steel seems to offer when it comes to softness on the trail. Maybe not quite up to a full suspension frame, but still, it's my frame of choice. I'm currently trying to find a good reynolds frame... maybe a jamis dragon, we'll see.
Just give it a try.
It's entirely possible that you're already sold on the idea that a FS is for you, but if you can find someone who will let you try something with a suspension, try that, too. It's a whole lot different on the trail than it is on the street at the shop. I too got sucked into the pretty shiny syndrome, and was looking at FS bikes a few years ago. I went with a hardtail instead. For what I had to spend, I got a lot mroe bike for the money going with a hardtail. And for XC, with a good shock (Marzocchi) and a good suspension seatpost (Cane Creek) I honestly don't bother looking back.
Back to the topic at hand, I can't speak to the bikes you mentioned specifically, but recently Kona has struck me as being a little more thoughtful when it comes to design than Trek. It's true, Trek is a mainstay of the industry so far, but they sometimes seem (to me) to be relatively conservative, so that they don't lose that ground. And I've heard of Fuels breaking.
Kona's also a mainstay, but I don't think they have quite the same name recognition, so they can get away with making more interesting and thoughtful designs. Right now, I have a trek, 2 nashbar steel frames, and a recumbent. Nashbar steel frames were made by scott, I built them up as quasi-beater bikes, that eventually got a little more attention anyway. And despite their status as beater bikes, they just ride really, really well. They're an absolute Joy. My next new frame will definately be steel. I'm looking at Jamis Dragon frames (reynolds 853 steel is very, very tough stuff, adn supposedly rides very well), azonic steelheads (if I decide to go the big, burly route) or a Kona steel frame... I'll figure out which when I get there.
None of which has anything to do with one of the main things you should find out, which is what bike feels better to YOU.
It's true a lot of this is talking out of my ass. But then again, that's really all I can do, because it's up to you to figure out which bike works for you. Try the "real" mountain bikes. Even the front shock can make a big difference in how the bike handles, and you may not need a FS. It'll save you big bucks, too. But most importantly, don't get in too much of a hurry right away. Yes, biking is really fun, and really cool. But biking is one of those things where it's very possible to spend a very unreasonable amount of money on something that may or may not turn out to be what you even want in the end. Or in the case of some FS bikes, something that may even break on you.