John, my opinion based on my location. Keep in mind this is a pizza restaurant with lots of kids playing.
DBA: Depends on your pricing. Most of my games are 50 cents/play. A DBA does not seem to make a difference at this price point in my location. If games are $1/play or reward you with extra credits for $1 increments, then a DBA makes sense. You definitely want a change machine. The location owners quickly tire of having to make change.
Coin mechs: The Iomex mechs with no moving parts are nice. But I've ran all different kinds of mechs and not really had problems with any. If they are gunky from spilled drinks, they'll cause problems. If they are clean, they all seem to work pretty good.
I put LEDs in all of the game GI. It keeps you from having to change GI bulbs and it means less heat and power usage. I don't use LEDs in inserts unless they are in hard to reach places that I don't want to mess with on location. I'll also use LEDs in certain inserts where heat can cause issues with raised inserts and wear. And example is Doctor Who's light matrix in front of the Time Expander. The lamp board traps heat and contributes to inserts raising and sinking. The reason I don't generally use LEDs in inserts is because some people hate them in inserts. And it can be distracting at times. So I take a middle of the road approach and generally keep incandescents in inserts.
Cointaker Retro LEDs are brighter than an incandescent. Often times this is nice as a little extra illumination helps. Comet's retro LEDs are closer to the brightness of a #44 incandescent. If you want a more incandescent look, they are the way to go. In both cases the color spectrum is a bit whiter than an incandescent, even if you use a warm white LED.
I use white rings and haven't had any problems. They do get dirty, but you can simply wipe the sling rubber and any other easy to reach rubber when cleaning the game. I do notice games with black rubber get significantly dirtier. So white does help keep the game looking cleaner. I'll take rubber that is a little dirty looking over a filthy playfield.
Outlanes, depends on the game and location. I play the game and adjust as I think is needed.
Pricing, I have a very generous split with my location. So I'm able to keep most 90s DMD games at 50 cents/play. A list games are 75 cents/play. Anything brand new will start at $1/play and drop to 75 cents after a while if play numbers drop off. I had WOZ in my location for 8 months and kept it at $1/play the whole time. It did fine. If I was splitting 50-50 I'd definitely price at at least 75 cents/play.
Other stuff: On WPC games make sure your connectors and header pins for the entire 5v power chain to the CPU are good and clean. I often replace the crimp contacts for the 9v AC at the transformer connector, AC input into the PDB, 5v output from the PDB, and 5v input to the CPU. Do this and you probably will never have a reset.
Play the game and notice any ball hangs or issues. If you see something happen or have to ever remove the glass, fix it. Little annoyances at home become big problems on location.