I spoke to a guy in Edinburgh Bike Coop, they stock the Specialized, Genesis and Comencal as well.
He said that he'd buy the Rockhopper without hesitation. Says it's got by far the best frame on a bike at that price, it was a high-end frame not long ago, and the rest of the spec is very good too. Although it doesn't have disk brakes it's got disk-ready hubs etc so upgrading later is simple. He's got the Tora fork on his bike and likes it, thinks it a good bit better than the Dart.
He didn't rate the Genesis well at all, said it was off the pace compared to other bikes at the price. The Comencal he thought was ok but there were parts on it you'd want to change and Rockhopper felt more planted and stable to ride, in his opinion.
He's had a couple of Kona bikes and liked them, very relaxed and lazy handling, but they don't stock them so he doesn't know what the current bikes are like.