From my research: it currently has not been possible to print overhangs greater than 45 degrees on models using the plastic extrusion process. I think the dual extruder allows the opportunity to incorporate a water soluble plastic material into the printing process in order to support overhangs.

On my really old cupcake i can get about .3mm resolution. You can do support material, you just cut off the extra material at the end. small gaps and mild overhangs don't require support material (like that rabbit).

parts are made out of a thin tube of plastic. it's liquid and bonds to the layer below, then cools and hardens. they're claimed to be about 1/3 the strength of straight ABS (lego plastic). you can print solid, which seems really really strong, but most things are hollow, or just a thin webbing inside.

modern machines can get < .1 mm resolution. apparently the cutting edge reprap setups are exceeding commercial machines' resolution.

i've had nothing but positive experiences with makerbot support. I got mine very early, the design was still quite rough. i'll probably build another 3d printers soon, but likely a mendelmax. I'm just a lot more competent now.

That said, any makerbot would be an excellent first 3d printer. relatively cheap, good community and commercial support, everything is open.

Reprap-derived FDM printers like the Makerbot use support material that can be removed after the print. This can be emitted by the various slicing software out there.