I've recently been reading through my copy of the Castles & Crusades Players Handbook to write a review, which got me started on a thread in the 101 days format at RPG.net. C&C looks like a good system for my fantasy gaming as it combines a lot of features that I was looking for, such as: unified mechanics, easy character creation, and a rule framework that allows ready customisation.
Weaknesses: with the first edition of the PHB the amount of typos is high and this can affect some of the rule interpretations, I think my biggest example is Power Word Kill where there are two different figures for the total HP of creatures affected. Not enough examples of play are present which is not a weakness for the veteran gamers that C&C has attracted to date, but is less helpful for newcomers.
Strengths: Price, C&C is reasonably priced; Consistent rules: pretty much everything works on the basis of roll D20 add modifiers and try to beat target number; simple and easy to learn, largely due to limited options, but this makes it easier to customise than 3e D&D where you have to replace existing rules and consider the impact on everything else.
Though I will still use other RPGs (Conan for example) I suspect C&C will now become the default fantasy system for me to use as a GM.
I'll start to develop houserules to expand my version of C&C with my blog as a workspace for this.