I own a 4400, and it's a good solid industrial machine. (It only plays LD's.) I was lucky enough to score one still sealed in the box several years ago. It will probably outlast me! The only minor hitch is no optical digital out. You will need a remote to switch CX on or off, but all other functions are on the the front panel. (Not really a problem if you're not using the analog tracks.)
If you want less problems down the line, avoid combo players altogether. Too many mechanical parts that can fail, especially the dual side players. My D704 crapped out all because of one tiny metal spring coming off!
If you anticipate dealing with any rotted discs, an early 80's top loading model like the PR-8210 can play these back with little or no speckles in the video. This was my first player, and still my favorite gas tube laser monster! And it's got industrial guts under the hood. :)
http://www.laserdiscarchive.co.uk/laserdisc_archive/pioneer/pioneer_pr-8210/pioneer_pr-8210.htm