i don't know any of the open source slicers. i have been using simplify 3d for the past 2.5 years.

as for rhino, not sure if any of you guys can qualify for the student version or not but that is really reasonable. if you are in school or you have a son or daughter or any other family member in school then you can qualify. you can get it from novedge who sells on eBay. its about $130. if your on a mac then the full mac version is fairly reasonable right now as well and the edu lic for mac is even cheaper....under 100 bucks i think. i use both. the key is to get yourself the videos from infinite skills. just watch both the beginner and advanced set and you will be using like a pro in no time. for a new rhino user i can't recommend those enough. i find rhino to be a very natural way to model. i have a bit of a woodworking background and find rhino workflow to be very similar to if i was to build something out of wood. someone mentioned the UI. the UI is extremely customizable. you can set it up pretty much however you would like. the command line is great. if you can't find that tool your looking for then just start typing the first few letters and the tool or command starts. very easy. sometimes i think of a tool i might need or something i want to do but don't know how so i just start typing and damn if a command or tool doesn't pop up in the list. its pretty crazy how extensive that piece of software is. you can download either pc or mac for free for 90 days. if you are interested in starting with it i may be able to help with some videos. just send me a pm.