Topeak Morph series every time. Only thing is be careful on the choice of model. The mount replaces one of your water bottle carriers and for most that means the seat tube mount. The "Standard" Morph length is long and if you have a sloping tube frame- it may not fit on the seat tube. For that reason I have the Mini Morph on two bikes and the standard on one.

There is an alternative mount system that is supplied using zip ties but it is still a problem to mount on some bikes.

I don't use CO2 as it is surprising how many times I have loaned out my pump when their CO2 has failed. And the same goes for cheap pumps aswell. Surprising how many times my Topeak works when theirs does not.