Hi Zee,
The "F17" has a taller carbon mast and is cheaper than an A3. I think that the F17 would be a better class to get into since it isn't an arms race like the A class is. You won't have to worry about having the latest boat since it is a 1 design(manufacturer) class.
Yes, it sometimes looks like an arms race around here. The question always is in this class; is your boat holding you back. I sail a modified 1996 Waterat right now. From where I sit, it seems that the real issue with these boats is not so much the hull shape, but the mast, sail and rigging that sits atop the platform. It is going to be a while before the hull shapes work themselves out. If I were looking at a new boat I would look at the A3, the Tool and the new Flyer, or possibly the new Scheurer Gen-5
www.messmer-seiler.ch/scheurer. Glenn Ashby is shipping in some new Flyers that will be available after the worlds. The Tool seems to be in full production right now. The A3 is modified from the A2 to give the boat better handling characteristics. The reports on the Flyer are great and not much has been stated about the Scheurer Gen-5 yet.
Anyway, back to the point here. Yes, the a-class is a development class and sailors are always looking for that extra .01 of a knot that gets them over the finish line one meter in front of the next boat. I still like this class, believe in the direction that it is heading (from stalled growth in the late 80's/early 90's to almost explosive growth today. So ask yourself what you want from a boat? How much do you want to spend? What is important to you in making this decision and so on? These couple of question will tell you whether or not to consider an A-class boat or to look elsewhere. If you continue to look at the a-class, post questions about the A3 to members that currently sail them and ask how they enjoy the boat. Try Lars at Guck Inc in Bristol and see if he will share his insights on the boat and class with you. Lars is who convinced me to join the class and buy a boat. Goodluck!