Yes, i believe it's a good option to consider because:
1. You can get it cheap, ~ $500. What options do we have at $500? 1-2 kw of some cheap generator?
2. Designed as both motor and generator for regenerative breaking.
3. If any part of the generator fails in time, there will be thousands of these motors/parts selling cheap
4. High power per lb, 80kw/130lbs
5. Can be water cooled, but i guess this will not be needed under 20kw