Django is used on some very large and high traffic websites and is just as capable (if not more so) of scaling to large applications. Arguably, you could say that learning Django is a waste as it may not provide you with much advantage if you already know Rails - however, if you are looking to move away from web development perhaps, there are more jobs in Python and learning another language is always a good thing anyway.

The Django documentation is fantastic and I recommend you give the introduction a go: https://docs.djangoproject.com/en/1.4/intro/overview/

You can use Django to do much the same things as Rails. Now whether it's worth the upheaval to switch across to a similar framework on a similar language, that's the real question. If you already know Ruby and Rails, you need to be dead sure it's worth the extra time switching when you could use that time building.

I totally disagree with your peers, Django is very well suited for larger apps.

As for guides, I cannot recommend something specific. Take a look at the docs, they had nice tutorial last time I checked.