Any of these cameras are the best?

Any of these cameras are the best?

Nikon D3200
or
Canon EOS 600D

and why

Which one is better?

Photography doesn't work like that, good photographers can get good results using just about any camera.

You should try a camera 'hands on' and make sure it feels comfy and is a nice fit, check the specification and make sure that it can cope with the level of your interest, and if you can afford to buy a camera you can grow into. I'm using an old Pentax 6 megapixel SLR that i've owned for 8 years and it still serves me flawlessly (and i've been taking pictures for over thirty years).

Both Nikon and Canon products are capable machines, both will give you years of enjoyment, give them both a 'hands on' and follow your heart. Enjoy!

The best camera is the one that feels right in your hands, so talk to a dealer. I wouldn't entertain either of those.