I absolutely love my Crown, it's one of, if not my favorite gun, period. I think that almost everyone who owns an Impact loves them too. They are beautiful, tack driving air guns too, but with a bit more adjustability, in a shorter, handier package. I would have bought an Impact but I'm a leftie and the Crown is more comfortable for me. I can't speak on the Galahad, I have no experience there but Air Arms does make quality products and I'd love to try one in the future!
I know you didn't ask about the Red Wolf but I'm replying to spray1mark's post. Most everyone I've heard from that owns that gun love it too. I would be thrilled to own a Red Wolf, they're sexy guns. I just can't justify spending $2400+$400 for the Red Wolf and programmer. I'm also leery of the electronics in the Red Wolf, that's just me. I like simple over complicated when it comes to air guns. For me it's just a question of diminishing returns with the Red Wolf, if they cost a lot less and came with the programmer, I'd own one. No question they're a beautiful and accurate air gun with great features, just too rich for my blood. My Crown is accurate, reliable, comfortable, sexy, easy to shoot well and does everything I want or need it to do and it was $1200 less. I love it!!!
As for the guns you asked about, I don't think you can go wrong with any of them. They're all great, well made products and very accurate. I posted a picture of a 8 shot group I shot this morning from 45yds. with my .25 Crown. I know the Impact can shoot just as accurately and probably the Air Arms too. I'm sure many will chime in on the Impact, Crown and Galahad and speak to the pros and cons of each. I'd love to hear more on the Galahad myself. Good luck making your decision! Stoti