usb floppy drives

[Mervyn & Giuliana Bond]

I have a library of old floppies.  Yesterday afternoon I spent 
several hours transferring floppies to my Performa with the intent of 
shifting them to my iMac for burning on CDs.
I've hardly scratched the surface and thought the purchase of usb 
floppy drive might be a sensible alternative.
Has anyone used these devices?
Do they read 2DD floppies (800k) as well as 2HD (1.44k)?
Advice appreciated.
Merv
--
"Science teaches that we must see in order to believe, but we must 
also believe in order to see."