How much does the length of a TT affect driving?

The length will matter most for what sites you can go to. We went from a 30' to 35' and have to choose our sites much more carefully. In some ways my 35' is easier to maneuver, it's arc is different. We will likely downsize when kids get older. I'd worry more about weight than length, make sure your tow vehicle is up to whatever weight your target RV is, with margin. Difference between 28 to 30' will be negligible.