I've found that most earphones on the market tend to fall out of my ears rather easily. These, on the other hand, are perfect. Once they are on I almost forget I am wearing them, and they never, ever fall out. They are perfect for sports - it actually takes a concerted effort to take them off.
The sound quality is excellent considering they cost £10. Nice and clear, not tinny at all, with a good bass response.
Yes, they look weird and some people are just unlucky to have ears that are the wrong shape for them. I would agree with the longevity issues - they last for a frustratingly short amount of time and one ear always becomes temperamental within 8 or 9 months. At this price though, i'd just buy another pair. I've been through 3 now, and i'll keep buying them until they're discontinued!