which five fingers exactly? their treks or sypridon's would be killer for hiking. I've got a pair of treks, I've backpacked, hiked, trail ran in them. uintas, wasatch, the swell, zion, etc. when you put in a lot of mileage on them, they dont' last as long as other shoes which is my biggest beef.
five fingers and minimal/barefoot shoes are the only type of shoe I wear anymore. I highly recommend them. BUT and a big but. you need to be ready for the bad stuff too - yeah you can roll your ankles easy in rivers. but if you're feet and legs are used ot a minimal shoe, you'll be fine - your muscles and ligaments will handle that. You have a much better ground feel with minimal shoes you know where you are putting your feet and know if you you're stepping on a bad spot. You become much more conscious of the ground and area around you. No doubt I can't walk as fast or carelessly as my buddies. which kinda sucks sometimes...but yet its nice. (dry) Sand in five fingers is not very fun.
You will change the way you walk, the way you see the ground. it took me about a month to get it down, and I still have moments where I revert back to heel striking. If you do get them - give yourself a while to get your feet muscles, tendons and bones strong again. They don't get used often in normal shoes, and because normal shoes have a higher heel than five fingers, your calf shrinks. it will take a while to get it longer (stretch daily..). and it will burn at first since your calf is used a lot suddenly.
their new spryridon looks awesome. it looks a little more aggressive than the old treks. I'm planning on getting a pair as soon as they become available.
http://www.vibramfivefingers.com/products/Five-Fingers-SpyridonLS-Mens.htm
http://www.vibramfivefingers.com/products/Five-Fingers-TrekSport-Mens.htm
the tresports as I said are what I use to hike in. I've found their other models are just not quite there when carrying around a pack or on long hikes. the slighter thickness (i think like 2 mm thicker) than the KSO's for example make a huge difference. mm's are big when you get minimal haha. basically bottom line - I love mine. and if you put in the work, you'll love 'em too.
aaaand deep breath...haha
this is one of the few areas I feel well versed in so ask away.
PS - if you don't like the toe thing, check out vivobarefoot (the neo trails or the new bretho trail) and inov-8 (especially the baregrip 200). both would be great alternaties. Merrell's trail gloves are awesome but I find that their omni fit stuff makes the shoe too confirming and the toe box doesn't let your feet splay out as much as I'd like.