I have done extensive accuracy testing with the 60gr SSS round in a number of rifles, one a purpose built 10/22 with a 1 in 9 twist Volquartsen barrel. Accuracy in 1 in 16 twist rifles (there were several in the test, all testing done at 50 yards) ranged from poor (1.55" 5 shot group average from a target rifle that detested it) to .492" average at 50 yards for the surprise rifle in the 1 in 16 group that didn't really seem bothered too much by it. The other rifles, while not as bothered as the bull barreled target rifle, hardly could be considered accurate; group size hovered around .75" at 50 yards. Basically, we proved what the rumors have said for normal twist rate .22 rifles - once in awhile you find one that tolerates the 60gr SSS round (although there will be an occasional unexplained flyer opening up a 5 shot group), most don't like it much, and a few, like the target rifle in the test, detest it and pattern rather than group.
With the 1 in 9 twist barrel it was not difficult to shoot .46" average size groups at 50 yards, and group variation (the difference in group size between the largest of 5, 5 shot groups and the smallest) was quite small, on the order of .06". We have not done extensive testing at ranges beyond 50 yards, but that limited testing has verified that shooting that round in 1 in 16 twist rifles at ranges longer 50 yards is a waste of money, even in the rifle that tolerated it, and the accuracy with the 1 in 9 twist rifle fell off after 50 yards, as mentioned in a couple of posts above. Also, as mentioned in a post above, watch out for the carbon ring, since the cartridge brass is about .22 short length.
Our final opinion is that the 60gr Aguila SSS round is a very satisfactory niche cartridge if you build a 1 in 9 twist rifle for it (10/22 Rugers are the easiest home project) and are looking to shoot a surpressed .22 rifle at ranges under 55 yards. If it's not surpressed and has a 1 in 16" twist or you desire to shoot it at ranges over about 55 yards, surpressed or not, stick with conventional std. velocity or subsonic rounds in the 35 - 40 grain weight range and a 1 in 16 twist. Oh, yeah, the one in 9 twist barrels don't get along real well with some 38 to 40 grain high velocity, standard velocity or subsonic ammo, although, in general, the 1 in 9 twist barrels are MUCH more tolerant of bullet weights in the "normal" range (35 - 40 grains) than 1 in 16 barrels are of the 60 grain round.