Cuniac, I am glad I can help you this time!
So I have a bit more storage... I have a 6x6TB WD Red NAS running on ZFS on CentOS with 2 disk parity, plus a backup server (because we all know RAID != backups) and off-site backups in two locations (of course). This is great for large clunky files (like the 15TB of bluray rips, TV shows and ~50GB of music I have). My boot drive, including OS X, dot dot files, ~/LibRary, Applications etc is ~140GB. However, for the 400GB (which is reasonable to expect it to grow at a rate of ~50GB per year) of VMs, small files with high disk i/o needs, photo thumbnails, photo editing in lightroom, large datasets, etc, the ~200-300MB/s I get from my disk array isn't fast enough. This 400GB of data also is accessible on my OwnCloud server (why trust dropbox with my data when I can run my own?) Which is why I needed to decide on how to best take advantage of SSD speeds for these files.
USB 3 speeds of 5GB/s is impressive and highly theoretical. Real world performance, even with an SSD, you won't get more than 250MB/s1. It's very sad. It leaves me to decide whether I want to put the files that need to be super fast on the same drive as my boot drive inside my laptop or spend $500+ on a thunderbolt 10GbE controller. I really don't want those files that should be on an SSD array on my boot drive, but I hate spending money...I guess given it's a ~$500 upgrade (before discount), it isn't that much more to do it right. I guess I solved my problem: I will get a thunderbolt controller.
As an aside, I don't get the high cost for Thunderbolt either. I guess it is because they can.
1
http://www.macworld.com/article/2039427/how-fast-is-usb-3-0-really-.html