Speedy love?

Hi all! I see people talk about how fantastic the speedy bag is, and I have never really been a fan. However, I find myself curious about it more and more lately and think maybe I should try one out.

Can you share what you love/hate about this bag, and share any recommendations, especially for size. I carry a wallet, cosmetic bag, phone, keys, business cards, reading or sunglasses on a daily basis so it should fit that comfortably.

Thanks!