If Operating Systems were вееr..
DOS Вееr:
Requires you to use your own can opener, and requires you to read the directions carefully before opening the can. Originally only came in an 8-oz. can, but now comes in a 16-oz. can. However, the can is divided into 8 compartments of 2 oz. each, which have to be accessed separately.
Soon to be discontinued, although a lot of people are going to keep drinking it after it's no longer available.
Mac Вееr:
At first, came only a 16-oz. can, but now comes in a 32-oz. can. Considered by many to be a "light" вееr. All the cans look identical. When you take one from the fridge, it opens itself. The ingredients list is not on the can. If you call to ask about the ingredients, you are told that "you don't need to know." A notice on the side reminds you to drag your empties to the trashcan.
Windows 95 Вееr:
You can't buy it yet, but a lot of people have taste-tested it and claim it's wonderful. The can looks a lot like Mac Вееr's can, but tastes more like Windows 3.1 Вееr. It comes in 32-oz. cans, but when you look inside, the cans only have 16 oz. of вееr in them. Most people will probably keep drinking Windows 3.1 Вееr until their friends try Windows 95 Вееr and say they like it. The ingredients list, when you look at the small print, has some of the same ingredients that come in DOS вееr, even though the manufacturer claims that this is an entirely new brew.