The air arms s410 has been consistantly on the upper end of the air rifle scene for years, I have had one for 12 years now and its never missed a beat. extremely accurate to the point of getting pellets into the same hole on targets.
I have never used a Co2 powered air rifle before but having to constantly by cartridges to go shooting would be a pain and probably quite expensive. with the pcp guns you need a dive tank, these can be had second hand in any dive shop for around £50 and wil last a helluva long time.... ie years. both mine are out of test now and still havent needed filling.
as far as power goes, I live in Northern Ireland so we need a firearms licence for anything but it has perks, my s410 is an export extra meaning 35 fl/lbs plus and " apparently" not available in England ( I'm not sure myself but this is what I was told)
another reason for a pcp over springer is the scopes they can use, the recoil from a springer will damage most scopes and any of the specific ones from springers are more expensive, a pcp has no recoil so any scope will do.
my other rifle is a BSA and I wouldn't go near them with a bargepole. it sheered off the stocks screws after 2 months and was away getting sorted for 9 weeks under warranty.
all in all its a fantastic sport and wish you all the best in whatever you pick. my advice is to read reviews on the top pic guns and stay away from the new tech ones that are unproven, go for a model that's been around and doesn't let people down