Folks who have them like them because they say it improves slow speed handling a lot.
VGs don't measureably improve takeoff performance...but they make the airplane feel more solid right down to a stall, with good aileron feel.

So.., ..why are we flying this slow for long periods that we need this "feel" changed? Isn't the sloppy aileron feel a good thing to warn us that we're too slow?
<joke>"Uh, yeah Doc. Everthang was goin' real good an' then WHAM! I wake up here with you!" <joke>
I mean, ... I land at places so short I can barely get back out of there, and if VGs don't get me back out of there .... why would I need to go slower and feel good about that? Virtually 100% of all places at which I land... I already feel good about. Why would I even want to fill out a form to win a drawing for them?
(No, I'm not trying to stir things up with those who have them and who clearly are glad they have them.... I'm just trying to figure out exactly what performance gain they provided that an unmodified airplane cannot also accomplish? So-far, these little things have worked marvels on high-speed jets and multi-engine Vmc numbers, but what are they really gonna do for a C-145 fixed pitch 170 "family car of the air"?)
(I believe It's a rhetorical question, and would encourage a wondering newbie to spend time practicing piloting skills than looking for magic bullets that likely won't even be on the next plane he flys. His improved skills will work on every plane, most of which do not have the things that feel good at speeds he'll likely never visit and shouldn't be attempting anyway.)
If you already have them, I'd certainly not spend any effort removing them, but if repainting the airplane....

(where's that little emoticon of that little guy stirring a pot..?? )
