Have you owned or played an MTD 535 or 635 before? What struck you about what you played - did you note the specs? Otherwise, my recommendation is to do some listening on youtube and demos and contact Daniel / Mike at MTD for recommendation. That said, while the results are all awesome, they can swing quite wildly from ones expectations (tone in your head). If you read up on the thread, you'll find many reflections on this.
I have not owned one before. But I think for me the the tone of the mids and highs really pulled me in. I want something that has a piano like sounds in the mids but still has incredible thump on the low end. I think about a precision low end sound with a jazz higher end if that makes sense. I guess I should just get a PJ bass lol