Does anyone use it regularly? Is it any good? But most of all, is it difficult to start using? (I'm guessing not).

I used to use it loads. Can be very good and useful, but like the rest of Office it can be so fucking frustrating when simple things don't work as you'd expect them to. I've wasted many an hour trying to get the Gantt chart to display properly/nicely.

It can't be that difficult to use since one of my colleagues in the US was able to use it, and she was so dumb as not to realise that we couldn't open her Project files because we didn't have Project installed. And this was despite repeated tellings.

Yeah, I used to have to use it all the time, but now it's pretty rare. I remember it being really frustrating how you'd setup a bunch of tasks that took a day or two each, and then when you rolled them up into a group the sum would suddenly be 15.326 days or something stupid like that, with no obvious reason where the fraction came from.