Will you be playing games? If so, that's a solid choice that you just linked. It's a bit pricey, but takes care of everything for you in one convenient package. Besides, it may be cheaper once you factor in the price of display port adapters.
If you'll only be doing spreadsheets or watching TV, then you could go with dual cheap cards and it'll do the exact same thing. Does your motherboard have multiple full length PCI-e slots?
If all you want to accomplish is 4 displays, then the simplest possible thing is two of these: http://www.superbiiz.com/detail.php?name=AT-567_VGA&show=p