1. I've heard about this from others. Your magnet may be defective. Mine doesn't usually slide.
2. Yes, I get pains in my left arm probably because I have it on too tight. Also I'm not a fan of how the edges of the band keep snagging my arm hairs (I'm not that hairy)
3. Be careful how you put your watch on and tighten the band. It tends to rub against the casing of your watch if you're not careful and leaves light scuff marks.
4. I've already called Apple and am returning the ML for a Sport band.
Same. Except the arm hair snag thing. But, I'm a woman.
I've got a 38mm SS WSB arriving tomorrow. I ordered two types to make sure I got my son his birthday gift on time and he likes the 38mm SS BCB that arrived yesterday, so I'm going to keep the new SS WSB and return my SS ML.
I like the feel of my husband's sport band, so I'm looking forward to using one of them.
I'll likely buy a Modern Buckle band for a more dressy look. If Apple ever actually sell them.