I keep hearing that Axiom has a trade-up program, where you can buy cheaply now, then trade-up when you can afford it later. I haven't seen anything on this website that officially describes it, but if it exists, then buy the EP350v3 now, then trade up to the EP500 in a year or so if you're not completely satisfied.

https://docs.google.com/spreadsheet/ccc?...amp;usp=sharing