Purpose: The purpose of this golf aid is to keep your upper body connected to your arms, so that you develop a body driven swing. This aid also has tracks that guide you thru the whole upper body motion (This means its a one plane golf swing: you swing on the same track on your backswing and downswing)
Set-Up: The set-up is the main issue people have with this swing aid. It takes some trial and error to get the size adjusted before you can use the device. Also strapping yourself in at first is a experience in itself, there are arm cuffs that Velcro in and these turn knobs that lock in the jacket in the front. But once you have it adjusted properly its easy to put on and get off.
Ease of Use: I recommend performing slow small swings at first, just to get used to the device. It took me about 20 swings to feel fully comfortable with the device. Once your body has adjusted to the new swing, it is the easiest device I have used to date because all you do is put it on and start swinging.
Effectiveness: The swing jacket has been the best aid I have ever purchased. It has taught me what a proper release feels like and what a body driven swing feels like. Within a few driving range sessions I was driving the ball farther and straighter. The main thing I want to stress about the Swing Jacket is that it teaches you by feel.
Longevity: I have purchased numerous swing aids and after a while I either get bored of them or they do not work on what I need fixed in my swing, so I stop using them. Not with the swing jacket, I can honestly say I will use this device for the rest of my golf swinging days. I currently use it on the range before my round or just do some swing in my living room to ingrain the proper feel.
Cheap alternatives to the swing jacket: Drills include putting a towel or head cover under the armpits and keeping them in place throughout the swing.
Golf Tips tv: Connection Drill will Help You (youtube video)
Rocco Mediate and Jimmy Ballard on Ben Hogan's Golf Swing and a Connection(youtube video)
Left Arm Motion - Golf Swing Tips For Improved Consistency (youtube video)
Other Site Reviews:
swing jacket official site
Amazon Reviews (scroll down the page till you get to customer reviews)
Independent golf reviews
World Golf Review