During the annual Chicago-to-Mackinac race on Lake Michigan a couple of years back, the boat "wingnuts" capsized and stayed inverted. Two crew members drowned as they were caught down below and unable to egress. In the Safety at Sea seminar I attended, the statement was made that the autoinflation feature of their vests made egress much more difficult, and the speaker made a case for the manual inflation variety. You pays your money, and you takes your chances... My choice is manual inflation. Mine also has a pocket for a whistle, a chemlite, and a Boye Sheepsfoot knife.
But I also crew on a 44' sloop for local races occasionally, and that influences my thinking.