There are a lot of reviews of all of the major players on the market at the moment. Just do a little research. Anyway, I'd summarize things like this:
The leigh D4R and the new smaller one (D16?) are probably king I would say. Others would probably disagree, but these seem to be the cadillac of dove tail jigs. High in quality, spectacular manual, very versatile.
I haven't used the akeda jig, but a lot of people like it. The dust collection is supposed to be better than the leigh stuff. It looks that way from the design also. I think the template forces you into
1/8" increments which would annoy me but probably isn't that big a deal.
A lot of people really like the porter cable jig. I think it doesn't do as much, but seems to cost a lot less and is still very good quality. Also less adjustable.
There's this thing called the katie-jig which you use upside down on your table router. Looks interesting but doesn't seem too popular.
Then there's the incra router table fence system with the micrometer adjustment. That comes with a huge book for making different kinds of dovetails.
There's the woodrat which seems more popular in the UK than in the US. Don't know much about it.
David marks has an episode of woodworks where he makes through dove tails on the band saw. That worked great.
There was an article in one of the woodworking magazines that talked about this guy who gets table saw blades reground so that all the teeth are at the dovetail angle. Then he cuts them out on the table saw and uses a scroll saw to cut out the waste. I know this article is available completely for free on the web. The major advantage here was that the pins could be as narrow as the saw blade thickness whereas on a router based jig, the pin can only go down to 1/4" which is the shank size on the router bit.
IIRC, the harbor freight and rockler jigs get bad press here. I believe they're the same thing.
Just google for each of these. There are about a dozen or so online reviews of varying combinations of these machines. That should give you a better picture than just one magazine article.
brian