Agreed........
There are so many variations on hybrids that it's tough to say one way is better than another. It really comes down to what you are looking for in your racquet performance. String and tension are a big factor but so is the racquet itself as some manufacturers have strict rules when stringing racquets (Yonex, Prince, Head to name a few), that can impact the racquets performance (racquet power, vibration, sweetspot, ball compression, etc.) and warrantee.
I personally prefer Gut in the mains and Poly in the cross in my Yonex racquets. The gut in the main gives me the old feel when I used to use all gut, but the poly adds a level of control that all gut did not (unless stung really tight, but then you lose feel) and it also lasts a little longer than all gut.
If durability is your concern, then a full poly might be the way unless you have arm problems or don't like the stiff feel. This is why hybrids are so popular now, as it allows you to customize racquet performance and feel.
Basically in general terms, put the poly in the mains if you want better durability, but put the multi/gut in the mains if you want more feel and comfort. Good luck in your search.
TennezSport