The only casino I really play at now is 3Dice and so, how about this, I'll do what I think is the best and the worst:
Best value, for me, is Industria. Probably 10 out of 10 - it's low variance, but my RTP % on this slot is almost always above 100% for any time period. Which, of course, means I have profited from playing it. I don't think any other game is as good to me - but of course, being low variance, the highest win is not all THAT high. Still, it's been good to me.
If I have one criticism, it'd be that the wild symbol does not multiply the line win, as it does on other games (typically, a wild doubles the line win, such as in Tutankhamun or Stick Shifter).
Worst value would be Ching Ching, for a few reasons - not the least of which is that my RTP% on this is really low, like 85%.
Visually, it's a perfect 10, in my opinion, but after you've completed the bonus round (free spins), a wheel drops down; you click on 'start' and it will spin, clicking on icons alternating between 1/2x or 2x (i.e., you're either going to halve your wins, or double them). This may just be selective memory, but it seems to halve wins a disproportionate percentage of times. I really think the multiplier wheel at the end was a bad idea - you are already spending in order to get the free spins, and you finally get them, and you are prepared for whatever winnings you earn, but then the wheel takes away half of whatever you won, even if your winnings were meager to begin with. I mean, I don't understand what the point of that was...?
I still play it, because as I say, it's pretty, and also there are times when you'll get really good spins - it seems to hit 5OAK frequently. But if there were one slot on 3Dice that they were going to retire, I don't think I'd miss that one very much. (But, I used to say that about Supersuits, and I changed my mind, and it's one of my favorites now, so there you go.)