I hunt both. Reasons vary but the climber has more advantages over the ground. Mostly use the climber when I'm familiar with an area and deer patterns. I have an old dove bucket(not with the swivel top) that slings over my shouder and is lightweight that I use alot of times when ground/still hunting. As I move around and find a place I want to sit for a while it comes in mighty handy. I don't like sitting directly on the ground because of the bugs and I might get my pants dirty! Just kidding!!!!! Actually I find it easier to reposition myself for a shot with less movement than if I was sitting on the ground. Also find it more comfortable and can sit for hours without shifting around. As a added bonus the bucket holds a lot of stuff as needed. I always keep 2 pieces of camo net in it to use as blind material if necassary, also handy for additional clothing or rain gear.
The majority of the deer I have killed has been in the climber. I use the API Shooting Star and when fitted to the tree correctly it is extremely comfortable, I have pulled my share of 11 hour days in it waiting for "ol mossy. There is also a safety factor when using a climber on public land that is crowded. Either way, it's all goooooood!!!!!!!