Honestly, the Overland won't be much less nice than the Summit you already have. You'll basically get a different color interior with leather that is supposed to not be quite as nice (I didn't really notice a difference myself), a cloth headliner, a worse sound system, and a more rugged looking exterior.
What do you think is too nice about it?
I've test driven both vehicles, and they are very, very different. The only things they share in common are the Jeep name and good off-road capability.
Benefits of the GC:
-Tons of features
-Quiet on the highway
-More toned-down/executive look (some people want this, some don't)
Benefits of the Wrangler Unlimited:
-Outstanding off-road ability
-Fun (everything about the vehicle is fun, from taking the top off to being able to hose out the interior and not worrying about mud/dirt)
-Iconic status- I'm not sure if there is a more recognizable vehicle on the road, nor one that has stayed as true to its roots or inspires such a sense of nationalism and American pride.
-Still lots of niceties, such as heated leather seats and navigation
-Massive, massive aftermarket that will allow you to customize it (or not) to your tastes (dealers also are very receptive to modifications on Wranglers and will not hassle you)
-Outstanding resale value
-Rugged, functional design that still looks great (again, it depends on the person)
Go check out both at the dealer. You will probably find that the Overland isn't too different from your Summit. The Overland and Summit will drive identically, so don't bother taking a test drive. Take the Wrangler Unlimited for a long test drive, and maybe even try to see if the dealer will give you one for the day. Check out some Wrangler forums. No offense to the JG Wrangler section, but it is, uh, dead. Wrangler Forum is my favorite. Spend a few hours on there and post a thread if you want. You will learn a lot and the members are very active and helpful. Depending on where you are located, you might even get an offer to go wheeling with one of them.
My take: If you still think you might want a Wrangler, get one. You will either love it or hate it, there isn't really an in between. Worst case scenario, you don't like it and trade it in for an Overland. The resale value is so good that you won't lose much, and would possibly end up breaking even or even making some money. For instance, Scottina06 had a 2013 Wrangler Unlimited that he sold after a few months and ended up making some money. The top of the line Rubicon X is probably what you will be looking at (although the Rubicon and Sahara can be optioned with the same niceties, just not stuff like the hood, bumpers, etc.) and will hold its value exceptionally well.
Let me know what you end up deciding. I hope I helped. Also, if you have any additional questions, I will probably have answers. I know the GCs and Wranglers inside and out.