I've recently converted to C&C and think they're a good, flexible and affordable option for indoor piggies. My tips would be to measure it all out and be sure of your design before you start building as it's a pain to try and take one part away again without the whole thing falling apart. Once you've done, cable tie it all together for extra security. (if you're using the connectors) If I was doing it again I would go for thicker correx than 2mm, it's quite flimsey and I cut straight through instead of scoring it on the first attempt.
And finally - allow a whole day!