I have started Prodibio, going on 4 weeks now so def. not an expert on it. I can say the it is NOT the same as dosing vodka. As I understand it Vodka and/or sugar dosing are to provide carbon source, ie. food/energy to initiate and sustain a bacterial bloom. That in itself is great however you may have minimal control over what strains are growing. In addition without following a rather stringent (as far as what I have read) set of guidlines, or alot of trial and error, you may end up with a single or mono-strain of bacteria, ie. one that has out-competed the others.
Prodibio could be consider to be more like Zeovit or similar systems except, you are not culturing beneficial bacteria, you are instead just adding them, providing supplementation for them and invertebrates/micro fauna with other prodibio additives. Does it work ? wish I could tell you , I do believe water clarity has increased and I do know it makes my skimmer go crazy. I believe sps coloration is improving, but again its only been 4 weeks for me so I cannot make any definitive statements. I am currently using Reef Booster, Bio Optim and Bio Digest
For a better insight into this product and how/if it works and what benefits you might obtain I would suggest that you pm gcarroll. I understand he has been using this for a bit of time now and I know he can give you a whole lot more information