To your point, seanheis1, OB's are thought of only in terms of having all cone-type drivers, but some of the best actually use at least one ribbon, magnetic-planar, or similar type driver, usually a tweeter of course, in combination with a cone woofer. And many OB enthusiasts are also planar fans, some having a pair of those as well as OB's. I mean, planars are just OB's with non-cone drivers!
And snapsc, you're exactly right, OB ownership places the same demands upon one as do planars---3 to 5 feet minimum from the wall behind them.
One incorrect thing said above is that OB's require a lot of power. Actually, one thing OB users like is the design's generally high sensitivity. Many owners pair them with low-power single-ended amps. One exception is the Linkwitz OB's, which require not a lot of power over-all, but a separate power amp for each driver. A fairly complicated x/o is a big part of his designs.
