Learning boarding will involve a lot of impact on your arse and knees, and possibly wrists – for a couple of days at least. Falls can be very abrupt affairs, leading to injury. Get a helmet, some pads and wrist braces for comfort.
Falls in skiing can be bad if you fall into the back seat and then your bindings wont release so well. Make sure you fall forwards for safety, and falls tend to be slower affairs as you are falling against the planks of your skis (think Michael Jackson in that video where he defies gravity).
Boarding is easier to get up to a decent intermediate level quickly.
With skiing and most ‘factory’ ski lessons, you will take a time to get near intermediate and can run the risk of getting stuck as a poor intermediate forever. But if you have decent guidance you should be ok, as skis are shorter, more parabolic and fatter nowadays and so it is easier to make good turns and carve turns.
In terms of ‘coolness’ there isn’t much in it nowadays – I tend to think skiing offers more potential for fun unless there is bucket loads of powder around.
Try and get some dry slope lessons before you go – it will pay off massively when you get to the resort.