The EX5R is the same as my EX5 except without the 76 keys. Great patches with flexibility to edit or create patches and layers. There have been some issues in some of the earlier versions concerning O/S and quantizing problems. But I haven't any problems as yet. I've had this board for about two years. The EX5 ads boast its 128 note polyphony. While this can be achieved it depends on what type of sound patches are used in the layer. It's usually alot less under normal conditions for me. I use it for live and recording work. It does weigh in at about 45 lbs. But the EX5R shouldn't weigh nearly as much.
I own an EX5R (rack) and it is a very deep module. You have sample playback,
virtual acoustic synthesis, analog physical modeling, and FDSP synthesis, all in one relatively easy to program module. You can even sample stuff with it but this is the weak spot: sample transfer is deadly slow, so it is almost unusable, unless you are a very patient person! All in all, it is great to program and it is a wonderfull studio module. But if you need tons of sample playback voices, you would be better off with the triton rack or the XV series from Roland.