HELP REQUEST

[Leonardo Cavallo <leo@dinonet.it>]

Hi all loopers

I'm new to the world of real time looping. My little experience is based on
the repetitive use of computer sampling, pre recorded DATs and the
incredible amount of sound layers from my .670ms delay (!!!). 
Now I'm looking for a looping device: a Jamman or an Echoplex.
I found 2 used jamman but I arrived lately: they were already sold.
Today I received this message: 

---- I have an ehoplex in mint condition with the footswitch.  Solid state
model from the 70's.  Make me an offer if interested.-----

I don't know much about the Echoplex... I know in some way it's more
efficient and versatile than the jamman (no flame here, please). The price
is higher and delay time should be longer. 
Someone can gimme more tech info about it?
And about the 70's models?
Some difference or modification in the years, between the old and the new 
ones?
Should I have to take in consideration for serious looping?
And for the value? I have not idea of the market value of this item... 

Any info will be greatly appreciated.
(I don't wanna bother you, so email me privately) 
  
Thanks
Leo