So I noticed on my third flight today, one my my PS3 motors has a high pitched whine / whistle when in flight ... has anybody ever experienced that, and should I send it in for looking at ??

i have that also with mine. was worried at first but its still going store.

Please turn it off and uninstall the propellers, then rotate the motors by your fingers to check it's normal or not.
Besides, everything shows fine on the APP, right?

I have the same issue on flight number 1 and 2 today. High pitched whine... I pulled the props and rotate the shafts in the correct direction and they all "feel" the same... Hoping you can see this video of my propless run test.  https://goo.gl/photos/qfScUbFz5BHvqghd6