I would ASSUME they're pretty junky. From what I've seen they're pressure decals, not waterslide, correct?
I don't have a tank yet (purchasing a HL Sherman as soon as they're back in stock at Amazon) but I was going to shoot for just trying to paint all my logos and lettering by hand. I know that's not everyone's forte, however.
I did a search on Google for "abrams tank waterslide decal 1/16" and found a few decal sheets on ebay that look to be waterslide. I have seen much more success using waterslide decals over pressure/rub decals.