Ballys Electromechanicals (roughly from 1960-1973), are easy to work on, as they were pre-computer. This is important to me, as I get a reel kick out of fixing a dead machine; big part of the hobby to me.

Budget is obviously important. If you can afford $400, then you can probably find a good working Bally on Ebay that's within driving distance, so you can avoid outrageous shipping charges. Pristine Ballys from dealers, however, frequently retail from $1,200-$2,500. If you can afford these prices, you'll get a fully "shopped" game, that will run flawlessly for years. The other nice thing about Ballys, is they kick out all the coins, and take an old-fashioned effort to pull the handle. If prices are no-object, you may find antiques from 1930-1950 turn you on even more. Mills machines are well-made, easy to work on and very collectible. You'll find some of the same issues as collecting chips - some people like "mint", some like played condition (my preference), some like restored and re-painted (to me, a cardinal sin - but equally popular among collectors as original condition machines).

Your state laws are important - you don't want the machine being confiscated! If your state is wide-open, then you can get a really modern computerized slot. I live in California, which requires that slots be 25 years old to qualify as a collectible antique - happily, all my favorite Ballys are right now becoming legal.

A word on your Pachislo Japanese style slots - collectors of all of the above mentioned slots tend to look down at the Pachislos. My main beef is that they have absolutely nothing to do with Vegas, Nevada, or US gambling history. To me they are junk, and a complete waste of time & money. Just my opinion.

Below is my best one, a rare "double" with original Hilton glass. Gals played this while waiting to see Elvis! Maybe the KING even played it for a while. Line-up any combo of bars, and the lites flash and the firehouse bell inside goes off, as dimes come flooding out of each side - TOO FUN!