The only portable (battery) operated models/brands of tennis ball machines that I'm aware of are: Lobster Grand Slam IV Lobster Grand Slam V Lobster Grand Slam V L.E. (limited edition) Silent Partner Quest How easy/hard is it to program various shots/drills on these machines? Is it difficult to "use" or "enter" the different shot/ball parameters you want into their respective control panels? I'm worried that it might be so time consuming and/or difficult to utilize the programming function/features on these machines, that in the end, one ends up not using it!? My other worry is whether any of these machines can really be programmed to feed "short" (closer to the net) balls. I'm not talking about drop shots. I'm pretty sure they can not do that. But I really don't know, because there is really no way to demo these machines before buying. I'm not concerned about these machine's ability to feed balls horizontally (left to right). I'm also not worried about their ability to feed deep balls. It's the vertical (short) ball that I would like to also program (mix in). What I'm hoping for and wondering is whether they can reliably be programed to feed balls to at least the service line. With the ball being launched from so low to the ground (I'm guessing about 8") its hard to believe, due to geometry, that these machines can really place balls somewhat close to the net. I would also like to know/hear about the "Pre-Programmed Drills" that come on the Lobster machines. I do not think the SP Quest has any simulated player drills. The Lobster Grand Slam IV comes with 3 pre-programmed drills. The Lobster Grand Slam V & V LE come with 6. For those who own or are familiar (played) with these machines - how do you like the pre-programmed drills? Are the balls/shots (speed, spin, short, deep) really varied and mixed? Are you given mostly deep balls or do the drills really challenge you with enough short balls? Are you really moved around the court at a fairly brisk pace? How good or different are the 3 additional drills that come with the Grand Slam V?