You know, I wonder about that, myself. My paintings usually don't stick around long enough for me to know the answer to the question. I use glossy medium varnish and I like it. I have tried the matte varnish and can't stand it. But, I do wonder how long it stands up. I have heard that acrylic varnish can be removed and re-applied without ruining the painting. Would be interesting to know if anyone has tried that.
I always put a clear coat on my acrylic paintings when they are complete. It makes the colors more lustrous and vibrant, plus protects the work.
I'd like to know of other artists' experience with different coatings: brands, any yellowing problems, durability, satin/gloss...let me hear your suggestions, please.
I'm shopping for new products to use...A)on my canvases, and B)on my painted furniture pieces. (Here's a heron table I sold last year.)