I have the Bantam .25 and it’s a great rifle. My primary use for it is dispatching pesty rodents and rabbits. It does a good job of this.
That said, I have been looking at the Wildcat .25 and find that it offers significantly more power. It may be more accurate, as well as quieter. I like to be as humane as possible when pesting, so the Wildcat is especially attractive being harder hitting and possibly more accurate.
There is a fair bit of price difference between a Bantam and a Wildcat MkII, however. If the extra money does not present a problem at all, and the purpose is hunting/pest control, I would go Wildcat .25. Otherwise, the Bantam .25 is a very nice and plenty capable option with money saving!