I used Functional Analysis of Rudin as a first book on the subject (self study) and it is actually the easiest of the three given that you know Topology.
Seriously go check it yourself.
But this book is shit.
Undergrads pretend to have read through it to boost their ego but chances are they have avoided a lot of the proof checking even in the first seven chapters, which I guess are the only ones people care to read.
This book is good only as an exercise book for the people who already know the subject.
Meaning reading the theorems and proving them yourself since the "elegant" proofs are shit anyway when they're not the most straightforward and clear way to show something.
It's not even good as a reference.
Why would I want to use as a reference a book I haven't actually read?