I have a reprappro mendel and it's a great machine i really love it however I am going to take some pieces from it and make richraps 3dr. It's another great machine and richrap is a very well respected member of the reprap community. Most of the parts are printable and everything is easily scaled up to make a larger print area. My mendel only has 11cm build height but the 3dr i'm going to build will be more like 1 meter build height. This is going to be a beast of a machine but you could always build it to the specs that rich has built which will give you around a 22cm build height.

here is a video of rich explaining his creation http://www.youtube.com/watch?v=11PVy4AUbeQ

here is a link to his build instructions http://richrap.blogspot.ie/2013_07_01_archive.html

Hope this helps with your decision. for me bigger is better. I have some big plans for that 1 meter build height. can't wait to get it going.