Is the sole gonna get flat in a week like any other regular slippers?

Absolutely not! I have been wearing these for 2.5mo and they are just like new! I’ve developed foot problems and was told I cannot go barefoot anymore, even around the house, and that I should buy some Vionic slippers. Well I didn’t want to spend $70 on slippers for that very reason, they wear out to quickly. The Sollbeam looked identical, was half the price and had better reviews. The sole was harder than I expected and wasn’t sure that I would like that at first, but I got used to it right away and they made my foot stop hurting almost immediately... now I just crave them constantly! I wish they made other shoes with the same foot bed that I could wear out of the house they feel that good...can’t wait to get out of my heals and into these at the end of my day!

Can anyone compare these to the Vionic Gemma slippers? Thank you

dI have both Vionic and Sollbeam. When new, they are nearly identical. Both are comfortable and have a great amount of arch support. The Solllbeam is slightly lighter weight. The difference is, the Vionic starts to wear after a few months (4-5). It looses arch support and stretches. I have been wearing the same pair of Sollbeams since January (9 months) and they have maintained their shape and arch support. My vote is for Sollbeam!

Is the arch support significant? I find shoes with a ton of arch support and that high arch uncomfortable.

So do I! The arch support is not as high as other slippers I've had. The lower "profile" is much more comfortable for me.

what is womens size 8.5 equal to mens size

Women's size 8.5 = Men's size 7. BUT: Their widths are wider, narrow feet beware. I wear an 8.5 wide, been wide width since little, Men's 7 are a good alternative when I can't find what I am looking for in women's 8.5 wide. Which sadly, turns out to be often, been that way since little.