Jury's still out on my JL because I've only had it a couple of weeks...so far, so good though.
My '80 CJ-5 has been extremely reliable, although I spent much time and effort restoring and maintaining in excellent mechanical condition. In 20 years, the only time it ever failed me, was when the original ignition module (and the only thing resembling a computer) finally crapped out, which is a common issue with most older vehicles, regardless of make or model.
My '99 TJ was rock solid for the 5 years I owned and drove it as a D/D and weekend fun machine...never an issue. In retrospect, I wish I had kept the TJ because it was easy to work on like the CJ, but practical and comfortable enough to serve as a D/D (for me, anyway). More importantly, it was a solid vehicle without all the unnecessary/problematic electronic voodoo, infotainment distractions, and plastic that's packed into the JL. Don't get me wrong...the JL is a nice Jeep (after all, I bought one), but I just prefer the simplicity and reliability of the older series.