Dreamer accepts Gcode. It's much quieter and sturdier, has a lot of fans for cooling stuff (head and case). Doors seem easy to break out accidentally. Case is plastic. Looks like a laboratory machine at first sight, but the overall feeling is cheap plastic, reminds me of one of those portable toilets. It has a touchscreen, but you have to push it with some force. Lots of options from Creator unavailable. It's a solid machine, good for use in companies, where people are not expected to tweak it.

The top is flat, so the cables and filament can get in the way when you print stuff, especially if you screw in the head without turning it around several times to get proper tension on the cables. Had issue with head hitting sides of the printer, losing steps then.

The new software, FlashPrint has some crazy ass license you have to accept, forbids any modifications and is full of lawyer bombs, tries to influence what you can and cannot print on the printer. Though it looks like Makerware with Skeinforge and Slic3r as the slicing engines. Doesn't let you change advanced parameters in software, though probably has config files in the folder. Didn't check.
I think the software license does not respect the licenses of Slic3r and Skeinforge, both of which come bundled with it.

AFAIK Dremel now resells their single-headed version of the Dreamer as their own brand.

I would recommend Creator if you want to tweak it, and Dreamer if you want a dumb printer that prints well ootb, with simple software. Non-technical people would love it.