I'm in my final year of an OU computing degree. I have to say I don't think it's as difficult as a 'proper' computing degree - I've no experience of a traditional degree, but this didn't seem very hard, although it can be quite a lot of work. There's more theory than I expected - only about half of my modules have involved serious programming (you can plot a path through the degree that involves more if you wish, but you're still going to have to do quite a bit of background).
It's not cheap - this year alone is costing me over a grand, but my work will hopefully be reimbursing me for some of that. I would recommend it though - it's well presented and you get good support.