I tried one of the glasses-clip-on mirrors before buying the first Mirrycle, but in winter they were often blocked by my jacket's left shoulder area being blown back and up in the wind. Also, I could not get it to be sufficiently stable. It was much better than nothing, but the Mirrycle mirror was always where I expected it to be, and always showed the same view behind me. It just worked.
We always remember the close calls. I saw a mailman's car approaching me in the mirror. When the car should have veered away from me, it just kept coming. I quickly turned the bike off the road and almost into the woods before stopping. He plowed over the area where I had just been. I don't think he ever noticed that I was there. Maybe he was sorting mail.
I have had the same jacket issue but just made some changes to solve that problem. Well, whatever works for you and obviously it does. I too have hit the side of the road on more occasions than I care to recall. The other thing to do of course is to have a blazing bright rear light. I thought mine was good but I saw one a while ago and I swear, I think it could be seen 3 miles away (night) and likely a good half mile away in broad daylight!