I clean mine with AG Engine and Machine cleaner. Then at shows I have always used AG Vinyl and Rubber Care, for day to day use they are a dust trap though.
I picked up a bunch of Turtle Wax 2001 Protectorant at Autozone when the 32 ounce bottles were on sale for $.99. It leaves the finish pretty shiny. I have used AA and AA Tire Foam in the past with good results.
When I wash, I spray with Simple Green and rinse. Once dry, I spray with Sprayway Non-Silicone Tire shine. Works great, is reasonable, and makes the next wash easy.
I use a brush and my car wash solution to clean. Never need anything stronger. I dress with Stoners Trim Shine.This is the only product I have found that is truly spray and walk away. Dries very quickly and evenly no need to buff. Looks just right too. Not too much shine and is not a dust magnet.