Top speed, flat out, on blacktop, 90 degree's, 2 old farts on board, big tool box, rear seat, cooler with 12 ice cold Mich Ultras, 2 folding chairs, and a pair of Cobra Walkie Talkies........Wait for it......54 MPH. Fast enough for me at nearly 78.

Hellz yeah!  Plenty fast enough!

On my Uforce 1000, 83 mph on speedo, phone app reads 73 mph. Thinking of larger tires will help correct the error.

Never thought of the phone app to check for accuracy of the speedometer.

This is the one I use;
https://play.google.com/store/apps/details?id=com.binarytoys.speedometer&hl=en_US&gl=US

I haven't had a chance to test the top speed of mine on level ground, but 50+ mph sounds about right.  Plenty fast enough for me.