Bought the Reebok Realflex at a local retail store and used them for about a weekend.  They are light and comfortable and had very good cushioning(insoles) for the heel. I've used it with and without socks and there hasn't been an issue with chafing in the heel or anywhere else. The downside, if you're new to "barefoot" shoes or prosethically designed athletic shoes be prepared to feel the soreness in your ankles.  On the first day of "breaking in" the shoes my ankles were killing me for two days.  Just be sure to take your time with them.

Athletic background:  I've been cross training and weight lifting for about two years and have used the same athletic shoes since college (6 years ago).  I just decided to buy these shoes because I recently learned the advantages of proper shoes for certain activitities and because I realized (the hard way) that my shoes lost most of it's treading/grip (it was practically bald). I don't run long distances (< 3 miles) so my opinion about these being good running shoes might be partial; however, I know a thing or two about what's good for your body ;)

Realflex vs. Nike Free's:  When I decided to invest in better athletics shoes I simply narrowed it down to these two shoes simply based on popularity, reviews, versatility, and friends' opinions. I also didn't want to spend more that a Benjamin on REALLY good and properly fitting running shoes (Asics, Saucony, New Balance, etc.) because I don't run much.  I tried both shoes on and hopped, skipped, walked, and jogged around the store on two different ocassions with two different friends and two different sales associates (for opinions) before purchasing one (a bit OCD? yes).  The issue I had with the Nike Free's was the form it MADE you run.  I underpronate as a runner, a little of a heel striker, and I have medium/low arch height.  The Frees' insole's had supportive cushioning at the heel but close to none at the ball of the foot.  I suppose to promote proper running on the ball of your foot with a mid foot strike in your run, but forcing a change in one's form can be costly to the joints, muscles, foot, and can lead to serious injury.  The Reebok Realflex has very equal and supportive cushioning throughtout the sole of  with more than enough arch support, which I feel is more versatile.  The Realflex can accomodate people who overpronate or underpronate in their stride because the sole is designed to move "naturally" with whoever uses it.  On the same note, the Nike Free's sole wedges out wider than the shoe or the footprint is wider than the actual width of the shoe; in other words, the sole is shaped like a trapezoid (I'm hoping this is understood) which again makes it hard for someone like me who underpronates to run the way I do, "naturally".  The Realflexs' sole isn't shaped like that (looks a bit convexed) and accomodates my natural stride.  Lastly, the sole grip on the Realflex is actually better/stronger than the Nike Free's (this I tested at the store both times with the sales associates there to justify).  The great grip on the Realflex is advantageous for tennis, racket ball, or running "suicides" on the bball court (which I hate, but is great cardio).

Hope this helps!  Happy shopping ;)