RaggTopp, 303 and Meguiar's Canvas Cleaner & Canvas Protectant are all excellent products. 303 and Meguiar's are usually available at West Marine and Boater's World stores so that may be a bit more convenient for you. I know the Meguiar's Canvas Cleaner does not need to be rinsed off and can just be sprayed on and agitated with a lint free towel like a quality microfiber. Does an awesome job.

I've not used the 303 personally but have used the RaggTopp products and find them to be excellent. Honeslty, I think you'd be hard pressed to choose between the three.