Given the choice between the two - I'd go sized AIO's - better chance of a better fit for bubs. CT's can be a little big round the legs for skinny chicken legged newborns - so I'd say not from the very start if you have a small baby ya know?

I used small bumg's AIO's for 6 months on Miss M so I got my money's worth there.

And also (IMO of course) true AIO's don't make the best night nappies if you were wanting to cloth full time. Better of looking into a fitted/wool cover combo or a good pocket combo or an AI2.

JMO of course