When I get on the highway, I have some bouncing at first, then in a few seconds once you get up to speed they even out and you have a perfectly smooth ride. They're super easy to install and remove, and are well worth it IMO. They're a zero maintenance item so you just slide them over the lugs with the tire off, put the tire back on and don't worry about it after that. I find them extremely useful when you get mud/ice built up on the inside of your rims from off-roading, then get back on the road. No more out of balance shaking with dirt and ice in your rims.

Here's a demo video of the concept of how they work:

 

I'm running 38/15.50-20 trail grapplers on my 95 open top.. I have run them for about a year and love them.. Noise is minimal and very similar to the toyo open country. Great all around tire .. The only issue I had was running in red clay.. They cake up a little and like most trail style tires, they get slick easier than the mud tire

 

I have 37x12.5-20 on my 2002. They're ok. Not noisy, took it to do some minor wheeling with good results. I got stuck in clay, but everyone did that day! I find the trail grappler a good balance of more off-road than on-road, but can do both. They also look pretty aggressive. Terra grapplers are more on-road than anything with zero noise, but can also do very minor off-roading and looks are so-so.