Why do my RAM sticks break (+ brand recommendation please)?

In my 2008 Mac Pro, I've had four 2GB RAM sticks break over the past two years. All sticks have been from OWC.

Perhaps I've been unlucky but I don't feel much confidence in this brand any longer (I've also had two Mercury Extreme crash). OWC offers excellent lifetime replacement warranty, but the problem is that I live in Europe and it is a hassle to send RAM and drives across the Atlantic. Of course, I was aware of this risk when I ordered the RAM initially.

Is there any way to check if something in my computer causes the RAM to break?

I'd also appreciate a recommendation for high quality RAM.

Thanks in advance
Philip