The Versa is really not in the same class as the other cars you mention is it closer to a compact car not a subcompact.
That being said it does get good MPGs and is ok to drive but not great it is very cheap to buy.
The Yaris is a great little car, it is like the Toyota of old, value priced, excellent build quality, simplicity, good durability, and easy and cheap to maintain.
The Fit is great to drive very practical, good reliability, with so so mpgs, and they are expensive to buy for what you get, if you do by the Fit DO NOT get the Sport model. The base model is just fine and much cheaper.
The used car market today especially small cars are not a god value . Essentially they are ripping people a new one that buy small used cars.
If I were you I'd go for the Yaris or Fit, buy either one new.
If the Yaris is cheap enough I would buy it first, but if I could get the Fit for about the same price as the Yaris I might be interesting in it because it is a good driver.
Remember do NOT go for the sport model Fit. They are a rip off!
Base model is the best value!