external eSata : same as internal ?

i was wondering will this kind of ports :

http://www.addonics.com/products/hos...a3gpx1-2em.asp

gimme the same performances of the internal bus ?

I'm thinking to buy the new MacBook Pro and a 2.5" SSD , the idea it's to use a 128giga SSD internally on the MBP and in case of need use the same disk on the MacPro with out open it ...

While i'm writing I'm thinking open the Mac Pro after all it's not a big job it takes only few minutes to install a new disk.

But I keep wondering if external eSata Bus are fast as internal .

Does anyone know something about it ?

thanks