Before I respond, can I just take the opportunity to point out the nifty little search window at the top of these pages. It quickly and efficiently searches all the Forum posts going back to the Hanging Gardens of Babylon. After 12 years of this stuff, it’s reasonable to assume you aren’t the first person ever to ask a question.
And getting back to that question, you’ll find a reasonably comprehensive answer (which I found with a search) HERE.
And you can test drive one system HERE.