A good while back [over a year ago even!] I finally decided to make my own wet palette. Some sponges, baking paper and a small seal-able tub. It couldn't have cost me more than £4 in bits.
So what do I think...? Honestly it has not revolutionised my way of painting as I'd been led to believe it would. I used it during the twin Imperial Knights and as I don't do a significant amount of blending anymore the primary benefit has just been keeping the paint 'alive'. Where I used a colour on the sheets it stayed wet for far longer than my existing palette. As I refuse to abandon my current palette I think the coating of paint absorbs a lot of moisture, in effect becoming a 'dry palette' making any paint put on it dry quicker than a clean one. So the wet palette has allowed me to come back to a blob of paint a few days later and still use it. However, I think I put too much water in so it has bled into the sponges which worries me as I can't tell if they've changed colour from the paint or it's actually mold - something I've been told commonly occurs if you don't use distilled water.
So, despite being marginally impressed I've actually switched to what I'll call 'micro-palettes'. You should find them easy to identify - they're Pringle's lids [clearly we get through a lot]. They're just handy to use, theoretically reusable too with a quick rinse under a hot tap and one less piece of single-use plastic going into land fill [for a while] or hopefully recycled but who knows nowadays?
I just find them really handy and particularly around Christmas I came away with half a dozen or so. No doubt I'll persevere with the wet palette for some things too, I certainly feel regret when dropper bottles squirt too much paint onto a Pringle palette and I know it'd be good for ages on the wet one. So, given my erratic and basic painting methods the wet palette gets a 3/5 for me. I'm thinking if I really wanted to paint a great model with some proper wet blending then I'd be more impressed but I no longer try to paint like that, so it's not as useful. For now it's an occasional help rather than a necessity.