A nice overview of the various sensor sizes out there. It doesn’t seem like there is going to be less variations anytime soon. Here’s 2 general rules:
1) IF all other things are equal, (and that’s a big if), then a larger sensor has more surface area to gather photons, and should perform better in low light.
2) Smaller sensors will have more depth of field
Ah, tubes. I remember being at a press conference, and having to auto register the tubes in my Sony Betacam by shooting a wire “In” basket. I don’t miss them, but like film, they had a nice organic “analogue” feel to them.