Noely
You missed the fourth "option" - learn to dovetail by hand! Not such a task, but it does take practice to develop the "muscle memory" you need. A bandsaw can be used to speed up sawing as well (especially useful for large dovetails). Jigs can NEVER achieve the really fine pins possible by hand simply because the dovetail cutters require a finite shank size. Also, with practice a small one-off drawer can be quicker made by hand. And isn't that what fine woodworking is all about?
On the other hand, if you are making a batch of dovetails, say half a dozen bedding chests then a Leigh makes some sense (providing they aren't taller than 24inches - the Akeda is limited to 16 inches) - the downside is that they can be a time-consuming pain to set-up. They are, however, robust and will withstand semi-industrial use. Pity is that we don't have the Porter-Cable Omnijig to compare it with in the UK. I'd recommend the 8mm shank cutters if you go this route - they are a lot more durable than the 1/4in jobbies.
I've had a look at the Akeda (local Trend stockist - trade day) and they don't seem to be anywhere near as solid, although set-up does SEEM to be a lot quicker (or maybe that was the slick demonstrator).
The Woodrat is an interesting proposition in that (I feel) it is more a sort of guide for hand-routing dovetails and is a great way to do larger dovetails and all sorts of other jobs.
I have both a Woodrat and a Leigh D-4 (both of which I use less and less as time goes by) so I'm a bit divided in my opinion here. I think you need to weigh up exactly how often you are going to dovetail - they are both expensive options to do something which can be done by hand with a little practice and a £15 saw...
If at all possible try out the options in the flesh before you buy.
Scrit