LOTS of threads about this already.
Fixed power ACOG compared to Variable power Elcan is not a valid comparison. Any of the quality 1-4x compared to the Specter is a better comparison.
Biggest cons to Elcan for me are weight, price, and eye relief. It's a good unit, but in MY opinion, you're better off with a good NF 1-4x or even a Trijicon TR24 series.