I have the 1/2 HP Vertex Mold spinner and I've never been happier with my purchase. The best investment I've ever made to my bowling game. Based on Vertex's website, both models have the same RPM, so the only real difference would be price and power output. Also, with only a $30 diff between both models, I wouldn't mind having that extra power for just a little more. I didn't buy any of the extras. I live in an apt with no garage or shop area, so I just don't need all of the extras.
My spinner has taken everything I've thrown at it. I've owned it less than a year and it's already paid for itself. I'd get the 1/2 HP. You won't be disappointed.