I have a soft top, and it's not the winter that sometimes makes me wish for the hardtop. It's the noise. The heater has no problem keeping up with sub-zero temps, but in any weather with the top up, it's just really noisy, especially as you get up to highway speeds.
Also, as Geoff pointed out, Jeeps have a lot of creaks and rattles, they tend to rust in certain areas, but the 4.0 will last a good long time. I have a 1994, and there are so many loose bits rattling, especially with the potholes from this winter making the ride even more bumpy than usual. The good news is that it's 16 years old, has been punished at times off road, has made several long road trips, including an annual trip to Hatteras, and after 112,000 miles, I have spent very little beyond normal maintenance keeping her going. This has been one of the most reliable vehicles I've ever owned. She starts every time I turn the key. At this point, I expect things to start wearing out, and so far, I am amazed that some things are still going so strong.
So, I think it sounds like a good vehicle. I'd still haggle and try to get the price lowered, but you should look around your area at comparable vehicles to see what a similar vehicle is selling for first. I checked Kelley for this rig in my area, and here's what came up for private sale prices: