It wasn't that long ago that MO'L was bitching about increased charges in EDI was it? What are the odds that any expansion at EDI is to step on EZY's toes?
Remember that Edinburgh is under new ownership now. Ryanair and BAA (old Edinburgh owners) have a hateful relationship so even if the new owners haven't done that much since the sale (I don't really know much about what's changed really) then the change of ownership itself is a huge leap forward from Ryanair's point of view. I'm not surprised by this really, I think Edinburgh is going to get some Ryanair growth, and EasyJet may well have contributed to their decision.
I doubt it will be good news for Prestwick on the other hand. I'd love it if they were to get growth but is there not an overlap in the catchment areas? A lot of Ryanair routes in recent years have shifted from Prestwick to Edinburgh, is this just the next round of this or is there or are Ryanair really going to make a go of it and increase them both. They are expanding at East Midlands, Liverpool and Manchester all within the same sort of area so could be the case in Scotland too!