if you have a computer that NEEDS 8 drives, and you only have 4 or 6 ports, thats why you get one, 2 slow ports, is better than no ports.
But also bear in mind that while max sustained speeds won't be possible(no sata 2 drive can do 3gb's anyway) say you're backing up every couple weeks, who cares how long it takes, its not vital. What streaming a high def vid, a 90minute long 8gb video would only need what 1.45mb/s to stream. Most things simply don't need speed, and most high performance operations require as much fast random read/writes and sustained speeds(maybe more random) which is again speeds FAR below the speed limits of that bus.
Keep in mind the Intel ssd which has by far the fastest small random writes out there, you're looking at 25-40mb's depending on how used the drive is. In other words, in reality that 133mb/s limit is barely a limit for anything but a few top ssd's and even then only from certain usage patterns.
