Two very different cars. The Ariya is upright and very well spec’d, the Mustang is much lower and well spec’d but less so than the Nissan. With the new options available (which is why I assume you’re asking) the MAch-e goes further than the 63kWh version but the Evolve has so much more equipment it’s unreal. It depends on what you’re after from your car but heated and cooled seats with memory function for seats, steering wheel and mirrors as well as powered tailgate, heated rear seats and a heads up display make the equipment in the Evolve far beyond the Mustang. The longer range Advance model still has electric and heated front seats and a powered tailgate but can go much further than the Mustang (up to an extra 70 miles).
Ride height and quality will be very different, all reviews comment on the Ford being rather bumpy while the Nissan is a less aggressive setup and more forgiving of the British roads.
I’d still try both and would test drive them both as well as the Enyaq. Only after you’ve driven them could you be absolutely sure which you prefer.
I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
I'll try to give my honest opinion but am always open to learning.
Mark