Lots of good comments here. I've dabbled with the VSH bee for the past two years, starting with breeder queens from Glenn in 2011 and then more in 2012. I've had 3 pure VSH and 2 Pol-line II queens. I used these queens to make lots of queens, mostly for myself, but with limited local distribution. I do not rigorously test for "VSH traits" in daughters. However, I do assess these queens as one would for any other type of queen. My assessments are pretty simple, and suited to my objectives of: high honey yield, mite resistance, and gentleness. Overall, my luck with the pure VSH was very poor. Honestly, I simply couldn't keep them from dwindling away, which was very disappointing and costly, even F1 daughters of pure VSH were poor - maybe this was simply bad luck. However, I've tried F1 daughters from other breeders with similar results. I know others have had success with VSH and I'd like to hear more about that.
The Pol-Line bees were completely the opposite - fantastic bees! Without a doubt the best bees I've ever used - and I've tried a LOT of different breeds and breeders. Again, my evaluations are simple: honey, mites, and gentleness. Honey and gentleness are simple to assess, with the results of the Pol-Line being much better than other bees I've had and better than others in my local area. For mites I routinely monitor using sugar rolls, sticky boards, drone uncapping, and visual evidence. The Pol-Line (breeders and F1 daughters) have consistently shown very low mite counts. How do these traits hold up without additional infusion of pure genetics, well that's a continuing story for which I'll have more data this season.
I realize that this doesn't address the main point of the thread, but a point to consider here is if you buy F1 daughters and they (and any potential daughters) last 2 or 3 seasons, wouldn't that represent good value? Sure VSH traits may not be lasting, but bees that survive and produce are certainly worthy of integrating into a breeding program.