USB3/eSata ext drive transfer speed questions attached to iMac mid '11

Ok,, I know that my Mid 2011 imac doesn't have USB 3.. So,,, I just bought a WD usb3/eSata external drive. It has an

eSata cable included , eSata connector that I plugged into my USB hub.. In regards to transfer speed,, What am I getting?

slower than USB 2? Equal?

My FW 800 is already occupied,, and of course nothing TB for now.. This Ext drive will be used as a stop gap measure,

and just wondering if by some sheer luck, and getting any faster throughput based on my first couple of lines .

Thanks for any input.

By the way,, in regards to FW 800,, any recommendation ? Seems liked we are locked into too FEW choices.