Assuming you mean a pro-style (safe for the home) range, Craigslist can have bargains. I got a year-old unused Gaggenau oven at half price from a guy, and it's working fine. OTOH if it breaks I'm probably on my own.

There's a lot of used gear from people who are remodeling, and sometimes dealers use Craigslist to get rid of overstock. With a dealer, I would ask if you have any warranty protection. With used high-end gear from homes, there are bargains because a lot of it is bought for trophy kitchens that get little use. But you're buying as-is, and remember that sellers are not motivated to point out flaws (see below).

If you are comfortable doing your own installations, or if you know a good handyman, it's a lot easier to assess the condition of stuff that's offered for sale. If you're not comfortable with the all electric and plumbing and gas details, and if you want a little bit of security and backup when something goes wrong, you want a good local dealer.

Here is a link that might be useful: Akerlof on lemons

I purchased a number of appliances from Craigslist. I purchased a GE monogram 48" Fridge and a Ge Advantium. I might have purchased something else, I don't remember! I also sold a new high end range on Craigslist. I had purchased something at a great price (floor model) and then decided I wanted something else. The buyer was able to get a very good deal and I didn't lose any money on it, so everyone was happy.

I say take a good look at it, trust your gut and go for it!