Ok, let me try this again. As a young teenager I used Craftsman raised panel flare nut wrenches (there wasn't the professional line back then) and Proto versions. The Protos were the combination Flare on one end with an open end on the other. The Craftsman spread a little, became loose on fasteners which led to rounding. I also broke a couple. However, the price was right and the warranty was easy. I never had a problem with the Proto versions.The Proto versions are still kicking over 30 years later but, they're SAE so they're not seeing much use these days.
In college I got a MAC set through the Votech tool program. They were very pretty and I really liked the feel of the wrench beams and the 8x10mm was really handy. However, I had problems with their 18mm spreading and rounding power steering hose ends on racks. About that time, the only tool truck visiting the dealership was Matco so, I got flare crowfeet and some Matco line wrenches. I didn't care for the thin profile on the Matco wrench beams as it tended to leave a nice crease in my hand if applying lots of pressure. The crowfeet were a great improvement but, I later found out that the way the wrench is beveled for easier attaching to the fastener actually reduces surface contact area and the 18mm spread. About this time, I surveyed what everyone else was using in the shop and what worked for them. Most were using Snap on. After searching for bargains, I came up with Snap on flare crowfeet, open end flare combination, and traditional line wrenches. Why is the Snap on flare wrench superior? It just is. For one thing, each size wrench is just the right heft and weight to it. The flare ends are machined like their sockets for off corner engagement of the fastener. The wrench ends are angled slightly sharper than others for improved access. Any beveling for faster fastener engagement doesn't reduce surface contact area. Lastly, whatever steel they use (must be comparable to the price of gold) doesn't spread.
Can you get by with a different brand of flare wrench? It depends on how often and how hard you use it. In a profession where time is money, you can't afford to have your tools let you down or cause you additional work.
This is just my experience but, after using Craftsman, Proto, Mac, and Matco flare wrench products, I prefer Snap on. To me Snap on makes the best #2 phillips screwdriver tip (but that's another thread) and flare nut wrenches.
