I can get either one for $999.00 new. I like the expandability, and USB connector of the motif rack, but the 2 space size, synth engine, and sequencer on the ex5r is intriguing since I can't recall any other rack module that incorporates its own sequencer. I am leaning towards the Motif Rack, but if anyone can make a case for the ex5r-feel free to do so.
Also, a motif question-if I get the DX plug in board it is supposed to have 900+ voices, but the motif only has 64/64 user voices available-what happens to the other 800? Will I be able to access them and assign any ones that I want for the 64 user locations? Same goes for the analog board. The motif Rack only holds 2 expansion boards, and I think I will be getting the DX, AN, and VL, and swapping them out when needed, but if I can only get 64/64 voices for each card I am definately not going to get all 3.

I've never seen or heard a Motif Rack. When did Yamaha release the Motif Rack and is it available in the USA?

It's being released in a couple of weeks. The jury is still out on it because it doesn't have all of the same presets of the Motif, or the sequencer, or sampler either, but it has 128 note poly, and according to yamaha an improved effects engine. I think I am going to wait until next year to get the motif rack.