You got me thinking about homemade vs. store bought, and this article out of several seemed to strike a good balance regarding permanence, how you clean them differently, etc.
Making your own Gelatin/Glycerin Plate ? Sharon Giles Art
I'm glad I bought mine; it's in as good shape today as on day 1, and there's support from GelliArt for questions/concerns, plus people at two LSS's who use them extensively. So $25ish (?) was a bargain. I've wasted far more $$ on nonsense, or good items I never use. Repeatedly. But it also sounds like homemade with glycerin work really well. So whatever floats our boats. : )
The negatives I read were more about another company's plate which is much thinner and reportedly doesn't take acrylic paint as well.