It's tough to ask because there's a lot of people displaying (partly justified) butthurt out there over D3, and just as many (partly justified) pro-D3 anti-PoE loyallists.
Basically, try PoE and try the D3 demo and see which you like more - D3 has more lockdown on skills, and provides a more 'structured' levelling system, PoE is more freeform. D3 has an auction house that optionally uses real money but a lot of people seem to think that the drop rates for rare items have been set so that it's impractically hard to reach 'end game' gear without grinding/buying cash.
In terms of graphics/sound/feel, I know people that will state a strong preference for D3, and people who will tell you D3 is lackluster and PoE is the be-all-and-end-all. I still love Titan Quest, so I'm not even getting into this one, suffice it to say both are fine as far as I'm concerned.
If you're like the guy from page 15 of this thread who feels personally offended whenever a game doesn't max out his hardware and fellate his optic nerves, you'll probably find both a bit of a disappointment - ARPG's always tend to be functional, graphically, especially with hardcore modes. Too flashy very often = too easy to die because you can't see what's going on.