I've put on Black Holes & Revelations. Just to see if there really is a massive gulf between even that and Drones-era output.
Listening to Map of the Problematique, I would suggest that there is quite a bit of a gulf there.
I think I hated absolutely everything on Drones.
There is literally nothing worth hearing on Drones. Black Holes & Revelations was a right letdown when it came out, but in hindsight it's not so bad. There are some good songs, or songs that became good in concert (I never quite warmed to "Map of the Problematique" in the studio but it's pretty enjoyable live). Drones makes me embarrassed to be listening for it, and disappointed that anybody willingly participated in recording it.
I'm not sure what's worse, Drones or that Dream Theater album, The Astonishing. Both are good examples of bands thinking they have a worthwhile message or story that is so poorly conceived it has the coherence of dog vomit.