Hello and welcome to the forums!
I have 2 flatlines, one for my XDs and one for the FNS9c. Both work great. I wear it to mow the yard etc. Just wipe it down when done with an anti-bacterial wipe and let it dry. No issues so far. My only "complaint" is that it takes about 5 minutes to switch from IWB to OWB. Other than that they are great holsters. Well worth the $75. Not to mention if you order from Comptac they send you smartiesHello and welcome to the forums!
Ive used various holsters, but never the Flatlines.
The kydex material is advertised as being impervious to stretching, sweat, and solvents, but how well does it actually work after wearing it concealed for days on end including when you do something strenuous and sweat on it directly?