So, I recently ordered some Secure X-Plus diapers to add to my stash. I figured the would be pretty similar to Bambinos, being made by the same manufacturer. What I didn't expect, though, was that the X-Plus actually seems thicker and more absorbent. I think part of it might be the big blue "gel" strip in it... I guess that would not go with the "baby" look of the bambino. I also heard someone mention that bambinos magically got thinner when they started selling boosters.
At around the same price, I think I prefer the Secure X-Plus. I do like the plastic of the Bambinos just a little better, though.