I'd say it all depends on the terrain, the cover and the time of day you are hunting. Both have their advantages and disadvantages. A complete hunter would keep either option in his bag of tricks.

Personally I favor tree stand hunting as you'll have a better field of view to pick up the movement of incoming deer. With an elevated vantage point, you'll have a greater peripheral field of view and will be able to watch more than one animal at a time. (Often important when focusing on a buck that's with a few lady friends). I primarily hunt stands of hardwoods either over a mast crop or along travel routes adjacent to bedding areas. Often times I have several trails within shooting range and in a tree stand it's easier to get a shooting lane to more areas. It's also better for rattling/calling as your sounds will carry further. Make sure you practice shooting from an elevated platform as your angular distance is actually greater than the linear, and your arrow will fall less than you'd think (aim low).

Ground blind hunting can also be very effective, especially where hanging a tree stand (or carrying one in) isn't practical. They are a godsend for setting up shop in a hedgerow along active crop fields, as well as in overgrown stuff like CRP fields. In cold weather, you can get away with running a propane heater and not have to worry about additional movement while trying to keep yourself comfortable. The movement of your draw cycle is also less of an issue when in the shadows of a blind. On that note, be advised that many of the blinds on today's market are quite crammed inside. So if you're planning on bow hunting from one of the smaller models, you'd better practice shooting from a kneeling or sitting position.

Happy hunting.