If you are a true history nut play the Eden. If you want the toughest test play the Jubilee. If you want a delightful round of golf on a course second only to the Old, play the New.
I agree with Bob.
Not sure about the history part for the Eden as its younger than TOC, the New and the Jubilee but certainly its got some great Colt design and more relaxed golf than the New or Jubilee. I would suggest that the New and the Jubilee are similar in quality, and better than TOC though without the sense of occasion that playing TOC brings, although The Jubilee is a degree harder/tighter but still with some very good golf. One thing to consider though is that at this time of year the courses take turns at playing off mats, one month the Eden then the next month the Jubilee etc so you may be restricted in choice if you are keen to play off turf.
If you're going out of town the original St Andrews Bay courses (Torrance/Devlin) and the Dukes have all had extensive redesigns/make overs since I last played them although the bones of the existing courses remain. The old versions were very good modern designs and I suspect the newer versions are as well. I've only walked the Castle but it doesn't look like the kind of course you keep a card to show to your friends afterwards. From what I've heard if you go with a mindset of just having fun, thats what you'll get.
Elie, Balcomie and indeed Scotscraig offer some old fashioned links golf with perhaps less muscle than the New/Jubilee, more like the Eden in that respect.
Jud - whatever you choose, I'm sure you won't go wrong.
Niall