The Sparkle Drive and the Bass-Drive are actually completely different animals in my experience... I've owned I think 2 Sparkle Drives and 3 Bass-Drives. They're both good pedals, but the big difference for me was that I didn't like the Bass-Drive's response to my wah pedals, whereas the Sparkle Drive sounds great with a wah. But if you're not using a wah, the Bass Drive can give you more options than the Sparkle Drive.
The Sparkle Drive is also quite different from the Hematoma, in this case the Sparkle Drive gets much brighter and snappier in the high end, whereas the Hematoma, which sounds great at minimum gain (that was my favorite setting with it) is also capable of much more gain than the Sparkle Drive. You can get a pretty heavily distorted sound out of it, but it does a really nice lighter overdrive as well. And once again, I didn't really like the way the Hematoma responded to my wah... if it responded the way I wanted it to it would probably still be on my board, it's a really solid pedal.
The DHA definitely sounds the fattest, yet I also found it to be very compressed, which can be handy too. I think it's absolutely excellent as a tube fattener, but I preferred running a separate overdrive into it as opposed to pushing the DHA into overdrive. Lots of overdrives sound great run into a tube preamp.
I've also had the Xotic BB, another cool pedal, but I found for me it got kind of muddy and not bitey enough for what I like on the E string. I don't think the Sparkle Drive sounds as fat as the BB, but it stays nice and clearly defined with plenty of bite and growl on my E string, all the way downtuned to a dropped C#.