The Athena kit is first rate and a real bargain especially when compared to that over priced stuff Rick Petersen is trying to sell.
The downside to the Athena or ANY mega-big bore kit is the weight of the piston. When you make the pistons that much bigger they get a lot heavier. It's unwise to run one of these kits without a fresh crank and main bearings in the engine. Bad things happen in a hurry when you increase the loads on an already fatigued connecting rod or main. This kit is not a good choice for riders who like to use the upper portion of the rpm range. Loads increase at the square of the speed, so more piston weight and high rpm complicates things in a hurry, unless you are really dilligent about your service intervals.
All in all a GREAT kit, and an amazing bang for the buck. The 290 with a Hot Cam and mild porting is a real Vet Class favorite.