Hard to beat Summits line up, they have several models to suit most anyone. I have a couple of vipers and they have been bullet proof for me. Hardest part is staying awake in them...
If you never want to buy another one, check out lone wolfs line. They are outstanding, don't let the price scare you. They are worth every penny.
I've been using an ol'man alumalite and have been happy with it. If i was in the market for a new one i would check out the ol'man drone
The SuperMag made by Austin Outdoors. Buckshot Manufacturing(the company that created it) is now making them again. I prefer the equalizer, but it is not available until next year. (I will be a buying an Equalizer as soon as they are available.) This is the only climber I have ever used and owned. http://www.buckshotmfg.com/videos.aspx Austin Outdoors Equalizer Leveling Treestand w/ Bench Seat & Backrest
I like mine as well but good gracious that thing is too heavy to carry in mountainous public land on every Hunt.
For me its Lone Wolf, for packability, weight, and platform size...I LOVE my Lone Wolf Alpha Hand Climber! Had a summit before this, also a great choice.
Can't go wrong with either a summit or Lone Wolf. I've had both and they both have a ton of positives and very few negatives. Good luck with whatever you choose!