FX Dream or Air Arms S510 XS Ultimate Sporter.

Dream for accuracy, adjustability, and a larger capacity magazine.

The Ultimate Sporter has superb accuracy. I think I shot my first 1" group at 100yds with that very rifle. It's long and heavy though, so it won't be a good choice if you don't like either of those things. The Ultimate Sporter stock is amazing, as is the buttery smooth action.

I haven't shot a Dreamline so I can't give any input there. But if it's anything like the Streamline with the ease of tuning like the Crown, I don't see how one could go wrong by choosing it.

AA S510 ultimate sporter. Its a proven design, very accurate and one of if not the smoothest action you can get. The S510 fit and finish is also at the top with very few that will match up. The ultimate is made in a full size and carbine model. 

Now that's a hard one. I had an AA510 which was a fine rifle, now I have a Dreamline Classic. Both shoot exceedingly well. FX wins on magazine capacity, but the AA wins on looks. See my review, FX Dreamline Report in the PCP section.