The arguement about how to store your fuel tank in boats has, can, and will probably go on forever. Here is my experience. Remember fuel stabilizer is just that, it will stabilize and slow the degradation of fuel in the CONDITION THE FUEL IS IN WHEN ADDED. It will NOT MAKE "BAD" FUEL "GOOD". In every boat I have owned and worked on I have never (yet) had a condition where the stabilized fuel has caused such a power loss or issue that it was noticible. This is from pwc's to twin engine powerboats (remember an extra person in the boat can usually make a noticable performance difference, so is it the fuel or the load on the boat causing the issue?) that "good" fuel was stabilized and then run thru fuel system when winterized.
As far as full or empty tank, I agree that full is better due to less chance of major condensation, but in my experience I have never (yet) seen condensation so bad that it caused IMMEDIATE problems in Spring. However, I do agree that the condensation over time will do damage to the fuel system with corrosion and the debris from corrosion (probably a majority of the fuel problems found have something to do with corrosion). It would be tough to argue that it is all from not storing the boat with a full tank of fuel though, you don't think there is any chance of expansion and contraction of the fuel tank while bouncing around in a lake or river in the middle of Summer (65F in morning and 95F during day) causing a reasonable amount of this moisture also?
I think the key point to be made in this discussion is to perform the REQUIRED preventative maintenence to reduce or eliminate the risk of problems in Spring. IE:stabilize "good" fuel, change water seperating fuel filters, etc.
Again, just my experiences and opinion.
* Another note, I think the fuel formulations have gotten worse in the past 3-5 years so my experiences with noticable performance loss may be "older" gas formulations.