I bought a Lone Wolf Sit-n-Climb this spring and paid $300.00 for it.
I bought it at the Deer and Turkey Classic from Andrae himself. ( the inventor of this stand) I think if you have to pay $500 bucks, I would keep looking because you can get this stand alot cheaper than that! Even on Ebay! You should be able to pick up the sit-n-climb for around $300-$360 dollars easily. Check out there website @ www.lonewolfstands.com
Anyways back to your question. I think its worth the money, its light weight to pack in and out of the woods, it folds very compact (about 3 inches), its absolutley quiet and its a breeze to set up and take down in the wood in the dark. Its also very stable when your set up in the tree.
As far as being comfortable, I would rate it 7-8 on a 1 to 10 scale. If your a bigger person, say over 250lbs. it maybe less comfortable with heavier clothes on. Remember these are my opinions based on the Sit-n-Climb. I have not had the oppertunity to hunt out of any other Lone Wolf stands, but based on people that I know, they are very satisfied with them. If you have any other Questions you can PM me. Good Luck with whatever stand you choose!