The first year had issues with the complexity of the system, noobs messing around with it on the lot and shipping people messing things up while the vehicle is strapped down.
They say the problems have been fixed, but I have not been around an air suspension that was worth a **** on any vehicle later on in life. That said, parts are cheap and its not rocket science to diagnose these days on Google.
If I right now were getting one I would probably get a Limited with the limited slip rear diff, 5.7 Hemi and slap on a 2" lift. But that's me... and basically what I have right now. Gas mileage suffers, but from what I've read the air suspension at full height is pretty rough if traveling fast. Like say a really rutted dirt road for long distances.
I can forgive Jeep for dropping the solid axles, but I do have a hard time accepting them getting rid of the limited slip front dif. That's a nice option to have in the sand and allows the vehicle to put power down without over-loading the brakes to control spin. Sounds minor, but on an extended beach drive that's tough on the brakes and helps keep momentum. They do require, at least on mine, 15K mile fluid swaps... so check and keep that in mind if you go this route.
If it comes down to the air suspension and you're still worried then plop down for an extended warranty. I had one on my first Grand and never used it and never would have needed it on my current one. The 5.7 is a stout engine and I'm liking it more and more as the Jeep gets older but I'd serious think about the V6 with the 8 speed the next go round. I no longer tow on a regular basis, so I don't really need the horsepower. I'm going to keep an eye on how the VMI diesel does out of the box as it is a very interesting choice in the market.
As far as I'm concerned the 4Runner is safe, but ultimately an over priced, underpowered, ugly barge with an embarrassing interior for the market. People like 'em 'cause they're safe and I'm fine with that; I guess. I don't have to understand. It's not my purchase and more power to them.
Buy what you like, and if you're worried get the extended warranty. Most people on here probably have one.
I don't think there's a vehicle made in today's market that 100K easy and reasonably trouble free miles is a stretch. Buy what you want.
[This message has been edited by p_bubel (edited 2/10/2013 2:12a).]