I have a double eagle P99 EBB pistol.
I've taken it to a proper skirmish - it was ok, but I'll be honest, I used it more as a joke weapon than anything else, as it cost me more to play at the site than it did to buy the pistol, then the 4 AAA batteries. But, it has performed better than a mate's £70 glock...
But seriously, I'd stay well away from Double Eagle.
As for the Skorpion - I'm afraid you'll be waiting a very long time for one. JG have stopped making anything (for the time being) (as of Octobre last year, IRRC, but there are rumours that they will be starting up again in a few months.
Either way, I haven't seen a JK Skorpion on the market since January 2009.
I'd avoid sniping for now, it isn't as much fun as people think it is.