First of all, you need to avoid these (and all Reefs for that matter) if you do not have a narrow foot.  Even those with a slightly wide foot will feel like they are cramped and falling off the sides of this flip flop.  Most flip flops fit my W/2E foot perfectly fine, but these are not even close to a comfortable fit.  The main issue is the narrow foot bed.  The secondary issue is the tight strap (though that will relax a bit after use).  I have found these issues across Reef's entire line.  Some people will recommend going a 1/2 or full size up to accommodate, but that just doesn't help.  I am a 10.5, ordered an 11, and it's still tight.  Went to a local store to try on a 12 and it was longer but still tight and narrow.  The longer size did offer a little more width in the foot bed, but my foot was still close to hanging off the sides and didn't feel stable.  Just compare a Reef to another flip flop and see how much smaller the foot bed can be.  When you wear a flip flop, you don't want your foot to fill the foot bed, side to side.  You want some room there.  That never happens with Reefs.  You will catch yourself looking at the tag to make sure you didn't get a pair of woman's flip flops.  That's how narrow Reefs run.

Second, if you don't have high arches, avoid this sandal.  The arch support is nice, but it is high, so those with low arches will just feel pressure all day long.  I have normal to slightly high arches and even I feel the pressure from the arch support.

Lastly, as a couple other reviews mentioned, these are basically glorified pool/beach flip flops.  They are built more for purpose than comfort, with a rubbery foot bed and gripping sole.  I doubt these are the pair you'd choose to wear to go walking around town in the summer months.  For about $20, you probably shouldn't expect much more than that anyway (though, admittedly, I kind of did).

With all that said, Reef does make a good product that lasts.  But, sadly, they have a very narrow market for their products, literally and figuratively.