I started using one last season with my TT.
I love it. I use the Beach Lane levelers with it. I mounted the transmitter in the right front cargo bay side. That way when my wife gets out of the truck to help with backing it in she can flip the transmitter on. It always takes two times to pair with my phone app. That's the only drawback.
Once paired up I can back in and see how level I am. Sometimes just moving back or forward gets the TT level. If not I then grab my Beach Lanes (Andersen Leveler clones) and back up till level. If just using wood blocks you can tell how high to stack them.
The other really cool feature is the 'Save Hitch Position'. Right after releasing the coupler you hit Save on the app. Then when re-hitching I can return the coupler to the right height for backing up the truck by hitting 'Recall Hitch Position'.
Add in the tailgate cam and hitching just got easy.