Buy it, buy it from somewhere with a returns policy if you are concerned you won't like it. This is always easier done from a store. Better yet, go to that store and ask them for a demo before you even buy it. Take your amp along and try the 4CM thing. I doubt there is a store in the land that would deny you a shot in advance of £1k worth of gear if they think you might actually buy £1k of gear from them, I'd phone in advance to arrange it though if you intend to take your amp to try 4CM. I think you'll like it if you spend some time with it. Just don't expect to sit down and have it sound perfect in 30 seconds, spend an hour playing on it. Try the amp sims you already know you like the sound of rather than wasting time on things you don't know you already like and actually play some stuff to get a good idea of how it FEELS to play through because it is very different to playing a real amp if you are used to that. Seriously, try it in the store, buy it and return it if it's not working for you. Nobody at the shop will care, it's just another day in the office for them. I expect you will end up keeping it though.