trying to find the right looping tool

[Bryanvandonslear@wmconnect.com]

I am new to the list and I am trying to figure out which looping device to buy.  I am mainly a guitarist.  I have been playing witht the digital delay in my guitarport which has a couple of seconds of delay and which gets dense very quickly.

My main reference for looping is Robert Fripps Frippertronics.  I would like to be able to have a looper that will basically do what Fripps equipment did.....loop things so I can play against them and build layers.  I am thinking that a unit like the line 6 unit, boomerang, or Boss loop station should do this nicely but I am not completely sure.
I also noticed in an ad in Guitarworld that Akai has released a new version of the Headrush.....it is E2 rather than E1.  Does anyone know anything about this unit.

I will be using the unit with a guitar port.  This has no effects loop so I am wondering one should put the loop unit ahead of the guitarport or after it.  

If anyone can shed light on these issues I would be greatly appreciative.

Bryan