I have had both, and loved my '94 XJ.  But I'll tell you, my JKU's are the best jeeps I've ever owned - and I've had a YJ, XJ, TJ, JKU ('07), WK2 hemi 4x4, and now a JKU ('16).  The JKU's were always sport or sport S models.
For the $10k difference, you can make a JKU perform like or beyond a JKUR for pennies on the dollar.  I have upgraded my sport S to Red Rubicon shocks and 19/60 coil springs, for about $150.  CraigsList and Jeep clubs/forsale forums are your friend.  If I put in lockers, I'd have near Rubi funcationality.  I have never needed them, for the wheeling I do, Jeeps 'BLD' works fine for me.
About the only thing that's $$ is an electronic diff disconnect, which is like $1700.  I'm too cheap, I'll just put in a quick disconnect kit - in fact, that's next on my list.
But for all around driveability, practicality, etc., I'd buy the JKU.  But I'd keep the XJ if I could...  and buy the JKU.  
Here's my JKU, btw!  2.5" lift, shocks, springs, spacers, and tires (35"s) for <$1500!!
