It's a case of risking it. €49 for indie license is pretty cheap. Alternatively play a very active role in contributing to the community (resources, tutorials, help, etc) or win the next competition or try to get on the VS team if you don't want to pay for a license. All of those roads are easier said than done though!
Extra alternative: buy a windows machine or mac (although mac build is currently not as stable as the windows build) although either one will cost you an arm & a leg in comparison to one of the indie licenses.
Originally VS had no asset restrictions prior to 4.0 & the only limitation was that you could not export your game. The asset restriction is more of an incentive to try to get people to purchase the software as anyone who creates 10 scenes is probably actually going to bother using the software as opposed to those who only make a few scenes & don't bother opening up the program in a while.
The build system though is not included in the evaluation version at all, as it is there to prevent users from compiling & distributing their games without purchasing a license.
In regards to the licenses... all the paid licenses use the same build. There is no difference in builds based on the license you purchase, although having said that, someone who purchases one of the top tier licenses is more likely to receive team builds of the editor / player if they ask for them (as & when they are available), than those using the indie licenses.