Wh20 man! Great pin. Total WPC classic!
Parts are all over, albeit can cost you if you have to replace ramps. Love the ruleset too. Oh and the topper parts are out there. The white backer, the decal, and the dome.
Next I'd grab JM. Difficult pin with a somewhat lousy theme. Hand can be an issue, but is fixable and there are parts and scads of info on diagnosing the little bastard.
Lastly I'd go with the JD. Im not a huge fan of widebodies. This one has a ton of stuff on it to shoot at.
(get the wh20)