Is it wise to choose a better journal with lesser number of similar papers?
Ask colleagues more experienced than you, ideally colleagues with experience of submitting to those journals, what they think of your chances.  

If there is a question of whether your article fits in the scope of a journal, you could also ask an editor whether they would welcome a submission such as yours.

Usually, though, it will end up being a judgement call. You could, of course, submit to your top choice, and then go with the other one if your paper gets rejected. This is quite commonly done, even if the top journal is a long shot. However, this takes a lot of time and effort, and in my opinion it is often not as good a use of your time as getting something punished quickly and moving on to new work.