I only do G1 and Masterpiece so I have no idea about BW, what a voyager is etc. Oh, I only own one G1 figure.
Beast Wars toys were and are absolute shit. Even when I started to enjoy the show, the toys are trash. Even the MP ones. The only 'beast mode' toys worth anything are the Dinobots. Last year at a local Wal-mart there were something like 20 monkey primes in the clearance aisle. The others just sat on the shelves.
Because they are garbage.
Voyager/etc are the sizes of toys. Depending on the line (Legends, Universe, Armada, et al) they are called different things but for the most part its:
Core Class - Your teeny tiny ones that usually cost like 8 bucks and transform by flipping one or two things. Usually about 2" tall. Think Go-Bots size.
Deluxe Class - The 'standard' size that you see just about everywhere. Not super complex but also not "ok I flipped one panel over and its done."
Voyager Class - Mid-sized toys. More complex, but not super crazy
Leader Class - are the slightly larger ones.
Commander Class - the big boys that arent stuff like Metroplex or Unicron
Titan Class - obvious.
From there we go into Masterpiece, but I wouldn't say MP is a higher 'class' over Titans/Commanders. They are an entirely different animal. MP is MP.