I like them. I used 2 different ones on my 5.7 2500, one big round one on my wagoneer, and i have one on my magnum powered wrangler. Those were different length and round vs oval but all 3" single. All had different results. The ram was the quietest. Wagoneer had the longest round one wasn't terribly loud but had a decent rumble at idle and got pretty loud at higher rpm. Pretty quiet cruising with od. i like to use the longest muffler that will fit.
My wrangler is loud. Its rumbly at idle, and loud when you step on it but it's a very short system. All stainless, 2-1/2 into 3" magnaflow Y with a magnaflow cat mounted to it and I think and 18" magnaflow welded right to the cat and a turn down.

Also have magnaflow cat back in my wife's 4.0 wrangler.
Some day i want to ditch the super turbos on the duster for magnaflows.