After trying VBS 68 Control at 27lbs & 28 lbs with 2 knot method..
String most similar to: BG 80. Has similar initial tension loss on the first 3 days, plays very slightly less hard, but has a bit more power. Tension loss after the initial plateau seems better, and it broke in 2-3 months, which seems about the same as BG 80. But they play similar enough that they are interchangeable imo.
If I had the option to choose one as a main string, I'd take VBS 68C. BG 80 is good but I thought the durability was bad because the tension loosened too quickly after the inital settling, which is the number one thing I look for in a string. It makes me want to cut it after 10-15 hours of playing time, and from there on, it constantly loses tension until it feels horrible. VBS 68C, I'd want to cut after maybe 20-30 hours of playing time, and from there on, it doesn't rapidly lose tension like the 80. It would lose tension, but at a lower rate, although not as slowly as a thick string like BG 65.
Key difference is that you don't mind playing with VBS 68C until it breaks, because it will still be relatively playable until it naturally snaps because the tension does sort of settle. Meanwhile, BG 80 doesn't make you want to not cut the strings, because it will never settle because it loses tension more rapidly even after a while, until it feels completely unplayable.
VBS 68C is a good compromise between the 80 and 65. Durability is closer to 80 than the 65, but it is better because the tension loss seems better. But playability is much superior to 65. If you ever wanted a string that played like BG 80 but loses tension less quickly, this is it.