Pete,
Now you've gone and opened up a can of worms asking about speed. Hopefully I wont get flamed for this.

I'll try to be as fair as I can here so I dont start something.

What I've seen is that an Acat is untouchable upwind, up to the point that you start breaking stuff, like 18knts-20knts wind speed. Downwind the acat goes "wild" and sails off the wind fast but not very deep. Wild is a downwind reach flying a hull. Most modern spin boats, F18, I20, F16, HT, etc can go deeper and will beat an acat dead downwind. But in terms of straight line speed, an acat is about even with a F18 or F18HT but the angles are differient. I have been out on my HT and an acat has kept pace with me on a reach and I had my spin up. I was sailing higher with a spin than you would in a race, and so was the acat, but we were about even, it was an interesting comparison. The acat has 14sq m main and I had up 40sq (main and spin), so that should give you an idea of the efficiency of the A.

Now in a race, the acat is still fast. Peter Johnstone came in second two years ago on an XJ, in one of the round Jamestown races. Charlie Barmonde and Ben Burley won the race on an i20 and I came in third on the HT.

Peter spanked everyone to the weather mark and then Charlie passed him down wind on his first or second jibe, because Charlie was going to much deeper, I passed Peter on about my third jibe and then I crashed, so Peter was able to pass us and we never saw him back upwind.

What Peter J/Landy/ and others were advocating is adding a spin to the acat, but that hasnt gained momentum. The class has been pretty vocal about the simplicity of the A and the easy of set up, etc. Adding a spin would take something away from the simplicity. Plus most A's are sailed in one design fleets, so it doesnt really matter the your vmg isnt as good as a spin boat, all of the other A's are sailing similiar downwind angles.

The other thing about the A is that it has a huge amount of development in the class focused on sails, rigs, and tuning. The only other boat with that much attention paid to it in rig/sail development and tuning is the Tornado. So you get very efficient sails, and very efficient rigs, and lots of used/spare sails. Good news/bad news here, you will be sailing against very talented guys with the latest technology and new sails, but I think thats a great way to become a better sailor.

Plus I like the fact that I can sail it alone, without crew, rig it in 15mins, move it around easily by myself, use beachwheels and not have to fool with dunking a trailer.