For me, Dynamex was okay!
I recently ordered something from Amazon (Canada) and saw that the shipper would be "Dynamex". Naturally, I went online to find out more about this shipper that I'd never heard of and was mortified after reading all of the negative feedback. I can only speak for myself, the package I ordered from Amazon was delivered to me by Dynamex on time, unscathed with no issues at all.
I'll be doing more shopping on Amazon in the next little while so I will be sure to come back and update this review again.