I work for a company that only builds gear driven rotary tillers. Obviously I think they're the best!
But seriously, to me, yes they are better. No idler or chain tensioner to adjust, and no chain to wear out. I'm not going to lie to you and tell you that you will never have trouble with a gear driven tiller. But I will tell you that our company has very, very few issues with the tillers that we manufacture. Make sure that you keep oil in the gearboxes, and you shouldn't have any trouble with it.
When you couple the six tines per flange, the fact that it's all gear driven, and the fact that we sell so many tillers, I think this tiller is extremely hard to beat. Especially in a sub-compact design. I don't know of anyone else that builds a sub-compact gear drive tiller.
I wish you luck with whatever you decide to purchase!