Michael,
I am not sure what Mark prefers but this is an interesting topic that gets debated and one that I have been testing with lately. I am curious to what others use to supplement their feedings. Honestly this is a worthwhile session for one of our general meetings and that might not be enought time to do justice to options.
I do think there is a ton of snake oil claims in beekeeping - but the feed supplement discussion on one off the bigger areas of debate between beekeepers. The old timers generally say sugar only is all that is needed but over the past 3-4 years I have been introducing supplements and "I feel" my bees are healthier. It is expensive but the bees eat it up.
I mostly use HiveAlive - the bees love it but it is expensive. I have used both the liquid and their fondant(superpricy) - I have even mixed the liquid concentrate into 50pd block of fondant - mixing efficiency ehhh, messy and a giant pain it the a##.
Other of many popular supplements:
- SuperDFM by Stong Mirobials
- HoneyBHealthly
I have even tried to reproduce the Hivealive by introducing a potpourri of essential oils - like lemon grass, spearmint, and Thymol oil in my sugar syrup mix- I just buy Hivealive now(I won't admit failure; it's just not as easy and I definitely didn't have my recipe down (and my wife hated me taking over the kitchen).
In short:
Try one, run a contol group, keep notes and let us all know what works for your bees - I am very interested in a bigger discussion of this topic for sure!!