I'm looking at moving into those. I have a lot of glass carboys, and 2 sixtel & 2 pony kegs. I love the sanitary fittings on the kegs and they're not so fragile.
And they are cheap, have handles and are easy to sanitize. And if I get back into brewing beer, I can cut one up and make a brew kettle with it! Yep, lots of good about beer kegs in winemaking. I'm surprised more people don't use them. I'm going to try and find a couple of used pony kegs (7.75 gal) to use in place of carboys. The fact that the Sanke fittings can be directly adapted to sanitary fittings is a big plus. Good luck and put up a pic of your set up with the kegs. If you have questions about what sanitary fittings to get, send me a PM. Here's on quick tip-The fittings you get from https://www.brewershardware.com/ are better quality than the ones you get from Amazon (which are OK too). Catylist Mfg also sells very helpful fittings for winemaking.