Considering the VTF-3 is $700 and the EP500 is $1200 (on their website), I'd go with the VTF-3.
The VTF-3 digs deeper than the EP500, and has a 350w/1400w amp, while the Axiom amp says max watts is 500.
Just judging from that, no contest for me - I'd get the VTF-3, even if the EP500 was the same price.
Actually I have a VTF-3 Mk2 in my 2600sf room, and it performs magnificently. If you really want to get the most out of your sub, though, no sub is all that "location friendly." Bass interacts with your room boundaries the same no matter what subwoofer it is. Experimentation and placement is key, and some inexpensive bass traps can really improve the sound more than upgrading the sub or getting expensive EQ equipment.