I'm not trying to downplay your product, in fact I'm seriously considering davmail running on localhost to use it, but if you're at the "looking into" phase of

I'm not trying to downplay your product, in fact I'm seriously considering davmail running on localhost to use it, but if you're at the "looking into" phase of supporting Exchange it's probably going to be a long way out. Most third party support that I've tried that isn't connecting to ActiveSync has been bug ridden. Different versions of exchange, different configurations, etc. I don't envy companies going down that path.