The issues of your concern
are not the ones you should be bothered with.
Any dinghy that needs to have the floors "installed" every time it is assembled is simply a PITA, and gets tiresome so quickly you'll wonder, if you do buy one, why you didn't listen up.
Whether wood or aluminum, you have to partially blow it up, and then carefully locate the floor boards and pop them in. It is a PITA.
The air floors, when properly inflated, do a very good job. Our 10'-2" air floor Zodiac is great and planes with three or four people with a 9.9 2 stroke. The floor stays solid. I had a smaller plywood floor boat, didn't plane, so can't personally advise on the difference, but I am comfortable with the stability of our air floor.
That said, there was a friend on another board who agreed, but also said that he would have to put up with the PITA for two reasons: he had a BIG dog with BIG sharp claws, and he only assembled his dinghy once a year (or once a century) when he went over to the Bahamas.


Other issue is size. In general, the longest boat you can afford is better since it will be more stable. The trade off is where to put it. With a smaller mothership the foredeck might not be big enough and you'd have to tow. Don't know where you are and what you hometown cruising grounds may be.
We don't know your situation when it comes to pets or plans. But at least you now know the issues involved in making the choice.
The West Marine advisors have a very good discussion of these issues:
http://www.westmarine.com/webapp/wc...tView?storeId=10001&langId=-1&catalogId=10001