I don't know much about these lovely tumblers, but I'll share what I know.
I've been collecting these for a few years. I have all sorts. I mix and match whatever I find at antique malls or on eBay when they are cheap. I have nearly a dozen now, with no more than 3 of any one pattern. It doesn't matter that they don't match. For me, the shape is the unifying factor. The size of these little beauties is roughly standard. Go figure. I find that when I bring home a new find, it's always nearly identical in size and shape even though I'm sure they are all from different makers.
As for which ones are more valuable than others (which is totally a relative term), I could care less about which ones are more collectible than others. (I sometimes hate using the word "collectible"... as in "these Franklin Mint kitties aren't junk! They are collectibles the children will inherit one day"). I really do buy what I like and what I can afford. I find the glasses usually go for around $10 each. I find some on eBay are pricier, but I won't pay that much.
I have a pair of Vaseline glasses similar to the one photographed above, but mine have straight sides, not slanted. While I don't have a black light, I like that I could make them glow if I wanted to.
As for uses, I actually use them several times a day. In the morning, I have OJ in one. In the evening, I have a glass of wine in one... very continental. And at bedtime, my sweet husband brings me an ice cold glass of water in one. I like to have water next to my bed. And yes, I do hand wash them. I can only imagine what my dishwasher would do to them. But there is always a price for beauty, isn't there?