I applied for International Business (with German) at Dundee for this year too, it's actually my insurance uni!! I went to an open day there a couple of months ago and I can tell you that it did seem like a very good department! Dundee University is seen as a good uni and has a good reputation, especially internationally. If you have any more questions then feel free to ask but i would recommend Dundee
I think Dundee would have a better social life. Think about it this way: you are spending four years at one university, so you'll have to live with the consequences that come with whichever one you choose. True, Stirling has a better Guardian ranking, but Dundee also has a good university. And when you apply for jobs and they look to your grades and experience, would rankings matter as much as the EXPERIENCE you've had and the skills you've acquired?
Stirling would be a good place to study as well, but keep in mind what kind of experience you would like, and where you think you'd get better training.