As a player…
For table games I prefer Boss Media. For all else I prefer Microgaming. To be fair I have to admit that I rarely play games besides Blackjack, Roulette and Major Millions Prog’.
As an affiliate I prefer Microgaming and Cryptologic.
Does the average player realise the difference in software? I would think that the average player believes the difference in software is simply because it’s a different casino. If you go into two different grocery stores you’ll usually find the same items, but just displayed differently.