While there's a ton of preference involved in sling style and attachment, I see the bulk of shooters move more and more toward the 2-point sling for most rifles...even bullpups...unless the guns are micro, sub-machine, and really short SBR's. There are so many guns/designs out there that it might hard to keep a discussion about it concise.
Anyway, as far as bullpups like the AUG, Tavor, RDB, RFB...and gasp...even my AR's go...I much prefer a 2-point sling like the Magpul MS line that I use. There are also other quality examples from reputable companies like Blueforce Gear and others. There's not just one brand, and these discussions often degenerate into brand loyalty. Over in the "sling" section of this site there are tons of discussions about sling type, but many/most do revolve around the AR. While bullpups are somewhat unique, I've found they seem to respond to the same beneficial control of a 2-point sling. I've done two SWAT classes using my Tavor, and the 2-point sling performed excellently.
I have used single point slings but only in a couple of cases like an HK MP5 and even a Kel-Tec PLR16 that is kept locked and stuffed under a truck seat. Both guns are short, compact weapons that do OK on a single point. I find trying to actually move around, run, or do anything slightly physical with a single point on a longer weapon to be unpleasant and perhaps even slightly dangerous in certain situations. Single points seem fine if you are static in a fixed position, but if your requirement to have this weapon requires that you might have to actually use it, you might find yourself having to run, crawl, or other to defend yourself or worse. I think that's when most might find a single point lacking compared to a 2-point.
Again, the variable in weapons, application, preference, etc. probably can't be covered here, but it is an interesting and often critical element.