Walaikum Assalam. You are right about parts and maintenance expertise since the last gen was here for very long. So the Vitz can be found at a better bargain than the newer Yaris.
Try to get a higher spec model like the safety edition 3, which has more features. Also try to get a verified higher grade vehicle with lower mileage. The bonus you’ll get with the Vitz is better rear passenger space, the new one is more cramped.
Having said that, if you don’t mind the lesser rear leg room, then the newer model has its own charm. The engine is more refined in this generation too, with the same or better fuel efficiency. Although it is the same 1KR but better tuned. Of course you will be paying more for this version.
