1. How do i know if my iMac has a TBolt1 or TBolt2 port?
2. What do you mean USB3 can be spotty?
3. Please elaborate concerning the USB3 funky sleep modes!
4. Suppose i have an ext drive that has 2 TB ports and i own 2 macs. Can i connect one Mac to make a TimeMachine backup on one port and the other Mac to make backup connected to the 2nd TBolt port? (Of course the drive would have 2 partitions so each would be dedicated to each Mac accordingly.)
1. You can open System Information and go to the Thunderbolt section on the left side menu, this will indicate 2x 10Gb/s or Thunderbolt 1 or 20Gb/s for Thunderbolt 2.
2. USB3.0 or USB in general sometimes will loose the connection and require a physical disconnect and reconnect to due issues communicating with the USB device.
3. Issues with USB are often caused by how they implement 'sleeping' for connected devices, sometimes it works, sometimes it doesn't, sometimes devices never come back online until disconnected and reconnected.
4. I haven't tried that setup however at the very least the two computers could be set to share the drive and be linked over a Thunderbolt Bridge network connection which would facilitate 10Gb/s transfer between the two computers and plenty of speed between the computers and the drive.
Ive come down to these two but i don't really see their differences!
Lacie d2 Thunderbolt 2
LaCie d2 USB 3.0
Go for the Thunderbolt 2 model, it's a newer version of their single disk solution, not only will it allow you to use Thunderbolt it has a USB 3 connection as well. Considering they are the same price it's a no brainer.