I bought the 500GB Comstar earlier this week, works perfectly fine with a 1.83GHz Macbook and an old G3 iBook (USB 1.1).
You can add up to 127 USB devices (such as hard drives) to any USB bus, so adding drives shouldn't be an issue for you. You might be thinking of daisy-chaining hard drives, typical with FireWire drives as they usually have two FW ports on the enclosure.
You can add up to 127 USB devices (such as hard drives) to any USB bus, so adding drives shouldn't be an issue for you. You might be thinking of daisy-chaining hard drives, typical with FireWire drives as they usually have two FW ports on the enclosure.