Selecting a ball machine that is right for you is all about finding the right balance between maximizing the features on offer that appeal to you, and minimizing the amount extra you'll have to pay to get those features. If money or portability wasn't a consideration, we'd all probably opt for the most expensive models, to get the variety of shot that will challenge us no matter how good at tennis we become. A machine that will spray balls across the court at all angles, speeds, elevations and spins. If you happen to be a 5.0 player or above, have your own court, or teach tennis at a club, this might be your best option anyway.
For most of us, our tennis skills, our need to transport the machine to a court, and a finite budget will mean that more than enough challenge can be found in a much more compact and affordable machine. If you're very young or just starting to learn the game, some machines might even offer too much pace and variety and be disheartening.
As a very rough guide, a basic machine is able to throw balls to a set position at a gentle speed, great for kids and those just starting to learn the rudiments of ball return. The Tennis Twist and the MM Rookie (right) are two such machines.
A basic professional model, (less than $1000), will likely have a ball speed adjustment from say 10 - 70mph, elevation adjustments for lobs, and a simple oscillator for firing to a couple of places, (lines), on the court to allow consecutive forehand and backhand practice or the same shot to two players. Machines in this price range include the Lobster Elite Freedom, Tennis Tutor Prolite, and the i SAM Tennis Ball Machine, (see above).
An Intermediate level machine should have a higher top speed, say 80mph, a more versatile oscillator to direct balls to most parts of the court, and a spin facility, usually just topspin or underspin, (backspin). These machines vary in price from about $1000 - $2500, and can simulate most shots of a real player. They can bring sweat to the brow of even an advanced player if their full scope is used, and battery life in battery powered machines will often exceed the reserves of it's human 'opponent'! There are more Ball Machines to choose from in this price range than any other and include most of the Lobster Elite machines, Tennis Tutor Plus, Player and Tower, Wilson's Portable Ball Machine, Playmate Portables and the SAM P1 and SAM P4.
Ball Machines in the top price range, $2500 right up to the devilish machine pictured below right, which won't give you much change from $30,000, are intended mainly for clubs, colleges, tennis schools or advanced players who need an advanced machine to probe any weaknesses in their game. The extra technology needed to create more speed, spin and programmable variety to their performance necessarily means more weight and less portability.
These machines tend to rely on an AC power supply as they're not really intended for use on a distant remote court - generally the tennis player has to come to them, though they can be rolled short distances on a flat surface.
Remote controls are more sophisticated, and programmability is commonplace allowing push-button access to a range of pre-set shot patterns. This is really useful for instructors teaching a handful of players at different levels of skill, or even within a family, with each family member able to easily select his or her tailored shot sequence and degree of difficulty.
Tennis machines able to offer these advanced features include Tennis Tutor Shotmaker, SAM Coach, most of the Playmate range, and now the new Lobster Phenom & Phenom 2.