Steven, welcome to Glock Talk.
In the early days -- forty years ago, for me -- the ammo situation was such that we knew most of what we had was crap, and we were so desperate for something better, we became willing to be the guinea pigs to see if new ideas and new theories that tested well in ballistic media would work on the street.
Time went on. We found things that worked. A higher velocity 147 grain bullet MAY be promising. It MAY work better than what we have now, which we KNOW works pretty damn good. I for one can no longer suggest that anyone become guinea pigs to find that out.
I don't know of any actual shootings with +P+ 147 grain. If you do, PLEASE reply here with details that others can check out. (Where the shootings happened, what agency investigated them, etc.)
Until then, call me old and stodgy if you will, I'll stay with stuff we KNOW works, such as the 124 grain +P that has been street-proven in so many gunfights from New York to Chicago to Las Vegas.