I was gonna post but you pretty much hit the jackpot here.
It takes a bit of time to learn it but that pretty much goes for any drawing software - and it's time well spent, believe me. There's soooo much it has to offer (much that I'm still discovering even after using it for a few months now!) and it's really the best of every drawing software people have been using up until this point (SAI, Photoshop, etc.) with even more added on top.
It goes on sale every so often, sometimes as much as 75% off, so I would highly recommend buying at least the Pro version. The EX version comes with full animating tools and a few extra rulers and print layouts, but Pro has everything you'll need to do an online comic. And if you do decide you want EX later on, CELSYS does offer discounts for people who are upgrading from Pro to EX.
I still use some of SAI to do my toning because it has some filters that I enjoy that CSP doesn't have, but if I ever figure out a workaround to this, I don't think I'll ever be looking back.