The size S is better but they still do get a little bit uncomfortable ...
927123
Based on the customer Q&A section, I ordered a XS (I'm a size 9). However, the top band was too constricting to the point of pain. Luckily the seller was generous enough to send me 1 size up free of charge. The size S is better but they still do get a little bit uncomfortable where the opening is after wearing them all day, although not nearly as bad as before.
4393498
Agreed that they take time to break in and get used to.  They are cute but not my most comfortable pair.
2240192
They are a little snug in some places and they tend to feel a little constricting. Hopefully they won't shrink upon washing them.
4106694
They are not comfortable but they do give you a little bit of something to grip. They could be vastly improved upon though.
1989448
A better fit shoe than the relaxed fit. However the tongue is still a little too long and rubs top of ankle
1792049
They fit but feels small or tight around the sensitive areas
4046404
Although they don't fit as fully as I want them to, I'd still recommend them.
3276476
Still getting use to them, they can feel heavy at first, but fashion comes with being uncomfortable for a while. Other than that. they seen strong an def. turn heads.
2154204
This pair, despite being the same size as my last NB shoes (although a different shoe), don't fit as snugly and securely. They move around a bit and I'm still having a little discomfort in my left foot.
2705361
I always wear a 38 in Birkenstock but usually I am a 39 in EU sizes and I wear an 8-8.5 in US sizes. These are similar to other birkenstocks, they hurt at first but then mold to your feet and become more comfortable. They definitely look cute on but they are less comfortable than the sandal (thong) style birks i had previously. After a few hours the top rubs and hits the top of my foot too hard and sometimes gives me a bruise; I tried loosening the top but that makes it too big. If you want birks you can wear everywhere and be comfortable, I'd suggest a different style with more top support, like the thong style or maybe even the Arizona since it has two straps. I've had these for a few months now and they are holding up well but I don't wear them as often as I wore my other ones. Overall good quality which you'd expect from birks but not as comfortable or supportive as other styles.
4794064
Good size, but the upper edges of the tongues are not that soft, which makes them a little uncomfortable at the front of the ankles.
2320889
These are great shoes but they have a slightly different fit than the regular TOMS in that they don't stretch as much or as quickly. I've been breaking them in for two days now and they are starting to give, but I can tell that they are going to stay snug.
3896903
Takes a while to get used to. The backside of the strap was a bit stiff and uncomfortable the first few times I wore them but has been getting increasingly comfortable with each use.
4800338
These aren't nearly as comfortable as the corso como dels. The nude patent is very pretty, but also very stiff.
Great looking but I wouldn't be able to wear them more than 30 minutes (back they went!)
They fit small. The 9.5 fit me. Im usually an 8.5-9 (in other brands... I have multiple pairs of the ballasox in a 10 and those fit fine)
1844933
They are nice and sturdy but kind of stiff and uncomfortable. I wish they were padded so they would feel comfier.
2492438
They do not have the same comfortable feel of other fitflops that I have.
317941
I wear US 10 and somehow this one is smaller near the toes which makes it really uncomfortable. I have tried it a few times and it's still tight, maybe it will take more time but so far not really happy with it. Having said that, the shoe does look good