I'll start by saying I don't think you can make a wrong choice here. Its nice when you start with that premise.
That said, I'd go the C&C route, for two reasons. First, your players, if they so desire, can get their hands on nice, new shiny versions of the Player's Handbook from their local game store or Amazon or whatnot. I've found (purely my own experience) that new RPG players like to have that option for whatever reason, or rather, they don't necessarily like thinking that they're going to have to dig for some OOP book if they want to read the rules themselves. YMMV (and YPMV).
Secondly, I think C&C is a better "glue" version, that is, its pretty easy to port things from any edition (including 3e) directly to C&C - easier than it is to port directly to B/X. I also like the ease of the Siege Engine rolls rather than having seperate tables for every class ability and skill, but thats just a preference thing on my part. Some people dig tables.