Personally, I'm not a fan of the Downtown Disney hotels. I stayed in the Marriot in 2003 (now it's owned by someone else) and while was a decent hotel, It just wasn't "Disney-fied" enough for me. For the same price, we could have stayed in a moderate resort at the time. I also wasn't thrilled with the DTD bus system. You should note that these buses run separate from the WDW bus system and just aren't as nice. And often times, you aren't delivered as close to the parks as a WDW bus. For example, the DTD bus system bus to MK lets you off at the ticket and transportation center and you have to take the monorail. I LOVE the monorail, but I would prefer to have the bus drop me right off in front of the park like the WDW buses do.
So overall, the hotels are fine - they generally are on the upscale side of things as normal hotels go, but they just didn't have the Disney flavor that I love about staying onsite. AND the buses left a lot to be desired for me.