If just the rear it may be worth it. If you have 4wd it may not be worth it. I heard the gear set on the front diff is welded to the carrier so you'll need a new carrier as well which just raises costs more.
Prices vary from $1k to $2k per axle depending on where you go. I would go to a axle or rear-end shop who has experience. I started to learn how to setup ring and pinions out of necessity. Had 2 bad installs done where 1) guy double the pinion shim and caused the pinion to scrap the carrier. Rear end had a whine that was awful. He told me to just keep driving it and it would break in. Refused to fix it. Second shop (XDP Performance in Wall, NJ) didn't set the backlash right, and the amount of play in the axle carrier was awful. It only sung when coasting. Its not that hard to do but you do need special tools and understanding of how it works and why. If you are on the fence don't do it, and just hire a pro who has done these.
I traded my 2013 3500 DRW Diesel truck at almost 1 year old because it had the 68rfe and 3.42 gears and ordered the same truck except built the way I wanted: added 4.10 gears, AISIN trans, bed camera, and aux switches. Cost me about $8k all said and done with dealer and that included the adders for the extra options. Worth it in my opinion. Towed completely different, but I was grossing 30k+ lbs. So trading the truck in is always an option.