In reply to Masonmarsh98:
The Edelrid Swift and Beal Joker are basically very skinny (so not very durable) single ropes that also pass the half/twin criteria. I would not use them for mountaineering unless reducing weight was the most important consideration, and I was willing to take the extra risks of cutting them on an edge (i.e. falling off was unlikely).
If you want to do sport or indoor, then you will need a single rope. For everything else double ropes will do - it is very common to use a single half rope for mountaineering-type things where you won't be falling off (hopefully!) like scrambling or moving together, and a long half rope can always be doubled up. For short trad (i.e. grit) or short pitches (tricky steps while scrambling) a 50m half rope doubled will get you up at least 20m (losing 1-2m in the knots at either end); a 60m half rope doubled will probably get you up a substantial fraction of less-exciting trad routes :P Obviously a 60m rope is a lot of extra coils to carry if you are going to use it moving together Alpine style.
For winter stuff fully dry-treated half or twin ropes are, I believe, the norm - helps prevent the ropes freezing up.
You can of course use a single rope for anything (trad/winter), since that's what most countries do, but I would prefer something a bit fatter.
My very brief guess is that the Beal Virus is just a very basic, cheap single rope - equally adequate for everything (particularly indoors/sport), although probably missing the dry treatment you might want for trad/winter (if it's raining I don't do sport?).
Post edited at 12:46