This appears to be a good deal to me also, but for the synergies, not just the new mine. After a couple of e-mail exchanges with Hugh Clarke, here of some things that hadn't occurred to me.

 Endeavour isn't lacking for rock.  They had months of unprocessed ore awaiting processing at Guanajauto.  They had a few rate limiters last year which they openly discussed on their mine tour. 

They lacked power going to the Guanjauato mill, which they needed for another crusher curcuit.  This was addressed, and have beginning to processi more ore.  They were also near capacity at Quancevi for processing concentrate.  Well, El cubo has a leach plant.  So, they will have less concentrate to ship, and will be saving trucking costs (and can process more concentrate)

They will be able to use the Las Tores plant until May of 2013 under the present contract.  So they will also be processing more ore.  I can only assume that there will be another contract established sometime in the future.  All this, on top of the additional reserves, and 2 operations within a few kilometers in Gaunajuato.  This for around 10-15 million shares worth of dilution to the shareholders?   Accretive dilution to be sure, and minimal at that.