I agree with alot Darra has said there. Fact is it depends on the person and thier skill level and preference, what is going on around can make a huge difference followed by their tollarance level for the down side to each game.
Lets face it, a full Fire works game that starts right away is 10 minutes of extreem concentration. If you can't make the cut for the final round it is a waste of time unless you are just trying to improve your game. If I do not have complete silence I can not play nore then 2-3 games of this. Lets not forget hitting the right window so you don't win and get less.
Another fact to face is Ned may be the only game where you have almost no possibility of mean players. If you speed wreck boats for 10 minutes I estimate 5 or 6 games at 20 credits so only about 600 credits an hour with nobody calling you names or saying anything ugly except Ned, and hey you did wreck a mess of his boats.
Music room you can get 25 credits every 20 minutes for playing and 25 credits every 2 hours for mixing a song. Thats 175 credits every 2 hours if you are dilligent. I have seen some ugly things in the music room though, hecklers, music rating people, lots of twin babys end up lost there and pickups (taken)
The old pitrates was faster but les credits. The new, I can do ok and the bonus and the keys can be ok. I rarely walk away from a game win or lose with less the 150 credits but it does happen. I believe you get credit when you get the keys even though it only says here is your key. I can play pirates while doing other things, it takes less effort and concentration for an ok game. The empty treasure is a big bummer even if you get credit. I find many more mean people at pirates then anywhere else in VMK. It can take forever to find a game unless you bring your own game, if I wait too long or get booted I will just play AI (oh I hate them) I know everyone thinks you lose credits with AI. It just isn't so. True you do not make much but you get keys a lot faster you get bonuses a lot faster and you don't stand and wait.
I have to stand firmly behind the mansion as the best source of credit for me and most. Player are usually polite at least. getting a game can take time, but usually not. I average 350 credits a game with 2 rounds of two on two plus bonuses. It takes more effort and concentration to win, but if you don't care about that they pay you well win or lose and bonus for playing on the same schedule every 50 loses is 750 bonus. You do have frequent crashes and some quits still. With DC gone most of the quits are because of poor movement.
If I am in a play mode, which I have not been I can earn 20K a day at any of the 3 major games or any combination of them. You just have to actually set your mind to it and actaully play the games not stand around scratching your heads. Lets face it selling everest cars is only going to take you so far and how fun is that?