I have had a Protector before and have the Toucan as well as the Boomslang DAC. The size difference between the Toucan and the Protector is negligible. From a single-ended source (iPod) you would probably not experience a big deal of a difference between them, except the Toucan is about half the cost of the Protector. Battery life seems to be about the same.
You will need to reterminate the TWag with the 6-pin balanced connector if you go the Toucan route.
To me--and I'm just burning in the iBasso gear--I wouldn't swap a Protector for the Toucan just by themselves. I have bought the Toucan/Boomslang combo specifically because of of both the DAC and AMP can operate in fully balanced input and output modes. The Protector is only capable accommodating a single-ended input, which is perfect for most portable sources.
A more appropriate comparison could be made once Ray releases his SR71B fully balanced (input and output stage) portable amp later this year.