
The original models had flaky extruders, which was thankfully fixed on the 1.0a model that I have. They also redid their pcb board, i think some chip was commonly cracked on the originals, I think those two issues drove a bunch of the negative reviews. Well, besides the proprietary filament thing.
The other major issue is leveling the bed is beyond confusing with their "calibrating utility". I put my machine so far out of calibration using it that i lost sleep trying staying up late and trying to fix it, only to make it worse each time. I didn't realize before getting the printer, but print quality relays heavily on an even bed. Once I learned to calibrate by just sliding a business card between the extruder and the bed as a spacing tool, my nightmare ended and prints started coming out perfectly.
Printing stuff from the internet is surprisingly easy. Just download from a site like thingiverse. Open it up in the slicer program and print. A few decisions you need to make on whether or not to make supports, how fast you want it to go and how fine of a print, but for the most part it is pretty straightforward unless you want to get crazy with the settings.
My biggest surprise right now is how much my wife has been into 3d printing the minute she saw it go. And she called me a dork for wanting one.

My kids a very little but they love it, too. I made some playdoh cutters for my boys and they have been enjoying them like crazy. They like to just watch the 3d printer go. (Another BIG reason why I needed an enclosed 3d printer. Little fingers that like to grab anything that moves.)