On my 2008 Silverado I had a catback dual exhaust with slash cut chrome exhaust tips coming straight out of the back under the bumper.
My 2013 has the side exhaust exit with the bowtie emblem chrome exhaust tip.
I perfer the first, but the second looks good too.
i had d/o the rear and i liked it until the exhaust moved and made it look like one side drop. I prefer to run either turn downs after the axel or before the axel depending on what i use the vechial for and i think it looks cleaner
I love the factory exhaust because of its corrosion resistance and it still looks great. I will likely keep the factory set up until I replace my cats that are close to dead, but need to find a stainless exhaust that will last like the factory one. The exhaust is duel out of the engine until the muffler then its single.
For me it depends on the vehicle. On my yukon xl I like the factory exit. Chances are if I ever do exhaust on it I will just duplicate the duel in duel out muffler and tail pipe setup. That is of course unless I come into some unexpected cash and do a Corsa system. Even then I would do the behind the passenger rear tire exit like oem. On my 95 I had them straight out of the rear with chrome tips on each side of the hitch.
I really think it depends on the vehicle and its intended use.
I prefer my exhaust to exit out the side in front of the rear tires.