Re: To get another Grand Cherokee or Wrangler Unlimited??
Make sure if he test drives the JK it's a long test drive. Hit the highway for a few miles and drive around town. Better yet get it overnight if they let you, used to do that all the time. See what he thinks about the highway performance and around town ability. If you drove your GC to the dealership he'll have a good comparison.
I'll bet he ends up going with the GC after a long test drive.