Honestly, I'd say that what is more important than saturation in a niche would be things that depend on you, personally.
Ask yourself four questions:
1. What topic do you enjoy?
2. What topic do you know well enough to teach others?
3. What topic has a process in which you are skilled?
4. If something fits 1-3, can it be explained in such a way that could be marketable?
My very first niche attempted has been the IM/biz-opp space. Now that space is saturated as hell, but I'm doing well with it. Reason is:
- I enjoy it.
- I'm good at it.
- I know how to explain it.
- I'm always thinking of new and different ways to market it.
It works for me, even though it's very saturated, and even though I began in it as a complete newbie.
Now, I would never ENCOURAGE someone to just jump into any specific niche if it is super-competitive, but if a super-competitive niche fits the above questions, I'd encourage them to follow it, because they've got a better chance of sticking with it ... which, in turn, is a better chance for them to succeed.