Wanikani is slow at the beginning. You will notice a significant increase in material after getting past the first few levels. Unfortunately, if you’ve already been studying kanji, there is no way to skip past the ones you know.

Pricing is
$8 per month for beta users
$5 per month if you have textfugu (there is coupon on textfugu page)
$10 per month after January once beta is over

I like wanikani and recommend it. If you already have a rhythm going with Anki though, it may not be worth it. If you do get Wanikani, I recommend checking out the unofficial apps for your phone which make doing reviews everywhere easy.

I’m very excited to see Duolingo’s incubator starting up. It will be interesting to see how the Japanese lessons will turn out!