Thanks for the nice welcome, Bunny! It's a great site you've got here- so many good resources and so much content to go through. I'll be back visiting regularly.
I already added my Children's Book Title Machine to the Resources section, as it's a really fun tool I built for brainstorming children's book ideas, but I'll keep adding more soon
To weigh in on the question of Amazon vs other self-publishing options:
I'll be honest and say that I've never used anyone but Amazon yet, but I know many other indie authors and those who've tried other sales channels like Kobo, Nook, iBooks, etc, have all said that the sales they get from those aren't worth it at this point. Amazon still has the vast majority of the buyers, so since I'm trying to get the most exposure possible as an indie author, I focus my efforts there.
Also, their KDP Select program allows you to use some of their promotional tools like giving away your book for free (which is a great way to increase your exposure and get reviews early on), run Kindle Countdown Deals where your book appears in a special section of the Kindle store with a countdown sales timer next to the price (I've found this to be very effective in selling books), and now be part of the Kindle Unlimited program, where subscribers to it can download your book and you get paid as soon as someone has read 15% of your book (which is easy on children's books).
Anyway, that's a long-winded way to say that at this point, I think Amazon brings by far the most benefit to indie authors and has the most reach, so I stick with them above the others. Their fees are very fair for what they provide authors, and it seems to me they're pretty committed to supporting indie authors. Plus there are no costs whatsoever to sell on Kindle or CreateSpace, which is really nice for us
Hope that was helpful! Thanks again for the nice welcome.
Take care,
Beau