I bought one this year and also found it extremely useful. Again you have to be in shape. Let me say that again, you have to be in shape. I deer hunt about 60 days out of the year and found myself using this tool 95% of the time. I have 30 different locations cut out so either I carry in a lightweight gorilla stand or the sling. The sling weighs less and is less cumbersome.

I agree with gzg38b you need to set up your trees completely opposite from a normal hang on stand. Additionally I use 6 pegs spaced around the tree to stand on. Normally I now carry in 18 steps (12 to get up and 6 to stand on.) When I first started using the system I got leg cramps but I worked through it.

The draw backs:
*leg cramps
*remember not to "swing." It's so easy to move you're whole body to look but you have to remember to stay still. I got busted a few times because I was fidgeting in the sling.
*Sore Feet. Standing on pegs in not comfortable. That is why I use 6 spaced around the tree. If anyone has additional suggestions please offer your suggestions

To make sure I got the exact height I used a T bar below the main strap. This gave me a perfect height for cutting lanes.

Benefits
*360 degree shooting.
*This system allows to MAKE shooting lanes when it's crunch time. (The RUT!) I can shoot behind, leaning and more.
*No one knows where you're hunting! No-one steals your best spot because no-one knows.

Earlier in the year I was running late to my stand. After I got up in the sling but my bow was on the ground a buck came in. I still had on my back pack, fanny pack with noise tree steps, bow on the ground, and my camo jacket was hanging in the tree. I was able to pull up the bow, swing to the opposite side of the tree and ready myself for the shot. That buck got lucky and never came with in range. But it just shows you how vestal the sling is.

This year I took 1 buck and 2 does with my bow. This was the best spent $169 bucks. I was very skeptical when I bought the product and only set up my new stands with this system. By the end of the season I switched over most of my stands to the sling.

FYI - I have another guy in my hunting party that also bought and loves to hunt from the sling. Once you go sling you'll never go back