Owning both a JLU and a 5G, I'll say they are different tools for different purposes. I made the mistake of trying to make my Trail edition perform like a Jeep on the technical off-roading and I made the mistake of trying to turn my Jeep into an overlander. And I'm not at all saying neither...
Don't know, but I suspect it's expensive. It has an 8 or 10 year warranty. That said, one issue is having an old battery when you go to trade or sell. That can hurt resale quite a bit.
I have a 5th gen trail and JLU Rubicon. I like the 4Runner better as an overlander and a better daily. The JLU is certainly preferred for a lot of off-roading (but not all). JLU is also just fun to bounce around in.
Build quality is night and day - Toyota all day long. I trust my 4Runner not...