We have played with several external drives and their connectivity systems over the years. Most of them do provide adequate performance; however, in the recent past as external drives have gotten smaller and moved toward USB-only power, we have seen the number of ports they take up and the impact on system performance go up. This was even true of the FreeAgent Go series until Seagate removed the need for the extra USB connection for power.
Now with the new Dock+ you are getting more USB 2.0 ports thrown into the mix. It is unfortunate that you cannot use the Dock+ without the external power (with just a single FreeAgent Go drive), but it still provides a nice "home" station for your FreeAgent Go or even the BlackArmor PS-110.
Over all, for the $29.99 price tag at Newegg it is a nice product that does exactly what Seagate says it does. We found ourselves leaving all of our USB devices plugged into the Dock+ (Mouse, iPhone Cable, Zune HD Cable) when we took our laptop on the road. This made un-hooking and hooking back up much easier and did not affect performance in any way. Even our CM Storm Sentinel Advance was unaffected, which was a good thing as it does not normally like USB hubs.