That tool-less design extends to what's inside the box as well. For example, the disk-drive sleighs can easily be pulled out after pushing two flaps toward the middle of the drive (photo). Removing the drive from the sleigh is also a tool-less job, thanks to four built-in pins (photo) that fit into screw holes in the drive.
I haven't clocked the exact time, but it should take less than a minute to replace a T300 drive -- a short wait that you'll appreciate if one fails when the server is up and running. It also helps that the SAS and power connectors are clearly labeled to help keep you from pulling out the wrong drive. Paradoxically, shutting down the OS will probably take much longer than that.
After using it for quite some time, I've found little to dislike about the T300. One, though, is the inability to mount more drives, which seems to have been prevented by design, because the server doesn't have a spare power cable beyond the two additional drives I mentioned earlier.
On the positive side, my test unit has reassuringly low power consumption: When the server is idle, my power meter registers a sober 130 watts, which for me, compensates for the limited number of additional drives you can stack in the unit.