Is it an authentic "Jeep" extended warranty covering everything the standard warranty covers or a "dealer/after market" warranty?
If it is genuine Jeep and the price is right I would consider it
, if its “not” Jeep I wouldn't bother, from my experience after market warranty's have limits on how much they will pay out on individual parts ie max $3000 on engine, $2000 on G/box etc.
I would ask for a copy of the warranty documents and have a read of what's covered and what’s not before I handed over my hard earned $$$ and if you sell before the warranty period is up is the extended warranty transferable to the new owner.
Besides its a Jeep, what could possibly go wrong?