It will be a difficult choice.
I have a V1 Mantis 10 Pro which has done me well with virtually zero issues. My only complaint is that their stem locking system even with their updates is IMHO, a “Mickey mouse” design. You will have some stem flex at some point, and it will make creaking noises. The Mantis is an easy to ride, quick acceleration, nimble ride that can go from the road to grass to gravel seamlessly. It will top out at under 40mph top speed (limited) which is annoying because it has the power to easily go to 50mph. There is more good than bad to the Mantis so I’m sure you will be happy particularly since they added some water splash protection. I have the 24.5 AH battery, it gets you long, long rides without fear of running out of juice.
The Ghost will be a reliable solid ride as well, except from what I read, range will be greatly reduced compared to the Mantis, that is an older design now comparatively but most people that own these are very happy with them and price is reasonable for all its features.
I also have a Phantom V1 second shipment batch, after my initial experience with Apollo being negative, this scooter has also been pretty reliable so far. This is a heavier solid scooter good for on / off road conditions.