I just finished my cabinet a few weeks ago, and it includes two 8-ways, a dedicated 4-way, and a trackball. When I first assembled the CP, I thought the trackball looked pretty slick in the center, but admittedly my first reaction was that the 4-way (which is kind of in no-man's land towards the player 1 side) cluttered up the look a bit.
The stick is a Happ Ultimate, which I stupidly bought before researching, and it seems like 80% of people hate it. Still, I have no regrets whatsoever. I would say that out of the embarrassing number of hours I've spent playing on this cabinet so far, it's probably been close to 50/50 between the 8- and 4-way (for games that use joysticks, that is). I really like the good ol' maze games (Pac-Man, Ms. Pac-Man, Mouse Trap, Lady Bug) as well as other 4-way games like Donkey Kong, Frogger, Q*Bert, and Qix.
I'm not sure why the Ultimate gets such a bad rap; personally I think it works great for every game I've tried so far except Frogger (because in that game you have to rapidly tap the joystick for discrete "hops" rather than just hold the joystick in the desired direction, and admittedly the Ultimate's throw is a bit on the long side). I guess it all comes down to what you're used to, and honestly, I never had the opportunity to play most of these games on the original cabinets so I'm a clean slate. I will say that I never find myself cursing the game for moving my character in a direction I don't want (try playing Frogger with an 8-way... ugh).
Also, for some reason, when playing 4-way games (especially the maze games), I prefer to reverse the roles of my right and left hands so that my right does the controlling and the left hits the buttons (if any). I think I developed that tendency through growing up playing these classic-style games on Atari 2600, which differs from just about every system since the NES in that you do directional controls with your right hand.