I still have a '97 TJ with the old AX15. While it's not unbearable it is definitely not as great as the later 5 speed in the '00 to '06 TJ I believe.
I would get a manual and one that is on a 2000 or newer TJ as it will have the NV3550 instead of the old AX15
Actually, I have the AX15, in my YJ. And, a freshly rebuilt NV3550, in my TJ.
I rebuilt the NV3550 myself and found some parts difficult to find since it is long out of production. The AX15 can still be bought brand new, and is rated at basically the same torque.
The NV4500 is easy to find parts for as it is a long time favorite super duty trans. used in lots of high horsepower vehicles. Expensive, though.
New Venture Gear was bought out by Magna International, who also bought out Getrag. The last of the "NV" transmissions were built around 2012, I believe.