Guys-My TT+ should be arriving today and I can't wait to get out and use it! I have about 60 tennis balls but they are pressurized (or, were at one time) and are of varying ages, brands, and flattnesses. I was thinking of investing in a bunch of balls for my TT+. I have heard that pressureless balls will save you time, headache, and money because they will last longer and be more consistent with the machine. Does anyone have a suggestion as to a brand or model of pressureless ball I should invest in? If I'm going to buy 100 of them I want to make sure I'll be pleased with the practice results and durability. Thanks for the help!