We recently upgraded our Series 1 to the Series 1 Pro. It's an expensive upgrade, to be sure, but for us we feel it was absolutely worth it. Ours was one of the older models, so it seems like absolutely everything except the metal frame has changed dramatically. The G2 extruder is a significant step up from the G1, and the heated bed has been a real game-changer (no more curling). Beyond that, though, there have been a lot of improvements. It's a lot quieter and a lot more accurate thanks to the new stepper motors, and I think the new material feeder and pinchwheel are a significant improvement as well. The electronics inside and the setup process has also gotten attention, and was a real breeze when compared with setting up the original printer.
Additionally, we're now able to print directly from Cura and Meshmixer (and probably other apps too, those are the only two we've tried direct printing from), the whole thing seems a lot easier to use and a lot less touch and go than before.
One area that was a real letdown was the webcam. It is absolutely terrible - very poor resolution, and not only manual focus but impossible-to-focus. Either they've accidentally fitted ours with a macro lens that's only capable of focusing on objects within a couple inches of the camera, or it's just a terrible piece of equipment that's unable to focus on objects on any part of the build platform. Here's a shot of the best focus I'm able to get on a current job...
It wasn't a high priority feature for us, but at some point I'd like to figure out some kind of better solution. We've warmed up to the idea of being able to use a remote camera to check on a job, and the idea of timelapse videos sounds fun, but the webcam that came with the Series 1 Pro upgrade doesn't serve up the image quality for either.
Overall though, we feel it's expensive but worth it.