I'm looking at a couple of Berkel and Hobarts (also one USBerkel - is there a difference?) 10-12 inches for $300-500. Anyone have any suggestions on what to look for? I like the idea of having a built-in sharpener, but how often and how do you sharpen one that doesn't have a built-in? Motor size? Model to look for or models to avoid. Any info on used slicers would be helpful. I would like to make a buy that will basically last me a long time with one outlay of cash.