> What are the differences between the jobs I could get with a B.Eng and M.Eng?

Once you've got to the point of getting a face to face interview - none at all, and then on day one of your job, your qualifications (even a PhD) in most reputable software shops become irrelevant to your colleagues.

In the longer term a masters can definitely help if you're involved with visa related processes.

If you obtained some specific domain expertise that is interesting to the employer in your thesis that can help. Then again, you don't necessarily need to do a masters to demonstrate such expertise. Creating and publishing applications, open source project involvement and the rest can be as valuable if not more so.