Bro i already said on higher speeds with continuous long running swift might be better but within city i have always found mira better than swift in each and every aspect.
If you are driving alone without any extra load than even pick/ acceleration of these 660 jdm is better than swift
Keep in mind i am telling this as per my 100% honesty because i own swift which i take care alot and love it as well and my father owns mira. But if someone asks advice from me i tell him the reality