I see, there have already been made a lot of posts about is, but I won’t read through all of them, so it might be possible that I say something that has already been mentioned. Since I am a WaniKanian myself, I will try to answer this question as objectively as I can.
WaniKani can be a great tool for learning Kanji, especially if learning with mnemonics is your style of learning. If you go at the fastest speed (like me), you can complete it in about one year, if you go at a more reasonable pace (like many others), it should take you two years. Regardless of how you choose to pace it, if you go through every single item, you’ll end up knowing about 2100 kanji and 6700 vocab (I’m not sure about the exact numbers, feel free to correct me if you know them).
However, there is one thing you should be aware: WaniKani alone won’t help you to learn Japanese. Sure, it gives you quite a few vocab, but you also have to practice reading, listening and/or production, depending on what you expect from the language. Since you use Anki for vocab, WaniKani would most likely mainly help you at learning Kanji, but, it does a great job at what it does if it suits you.
I’ve heard many people complaining, however, that WaniKani subscriptions are rather expensive, and I see what they mean, as the prices are about double the prices on Bunpro, but on Bunpro, you learn grammar and also have the possibility to learn vocab. This means with WaniKani teaching kanji and vocab, and Bunpro teaching grammar and vocab, I’d say both of them roughly teach you the same amount of items - I know that 1000 grammar points are way less than 2100 kanji, but if we’re talking about the total amount of items you can learn, which is for both above 7000 to 8000, I think, it is indeed not really justified by WaniKani to make you pay double the price that you pay for Bunpro.
Another aspect you have to be aware of is that WaniKani can easily end up taking most of your time that you use for studying Japanese if you don’t pace yourself carefully. I’ve read many posts of folks that achieved level 60 in one year saying that their general Japanese skills are somewhere around N4 to N3 (and I hope that I won’t end up in the same situation lol), while others who went a bit slower with WaniKani had passed the N2 around the time they got to level 60, for example.
This is a bit unrelated, but might perhaps be interesting, especially regarding the pacing. I haven’t “officially” stated it yet, but my goal is to get to N1 level in one year after I initally started learning Japanese. My background with Japanese back then was zero, the only thing I knew where two words, these two being こんにちは and ありがとう. I do not plan on taking an exam, as I am doing this for myself, but in one year, I will try to find N1 test material somewhere to test me myself if I am that level. Now, this might seem to be a contradiction with what I said earlier, but I have a lot of time to study Japanese every single day, in general, I usually do four hours of studying and practicing every single day, from Monday to Sunday, but I could basically also just do five or six hours a day, I don’t really have a limit of how long I am able to study (except for the natural rotation of the Earth that causes night and day, of course). But, I still try to keep it at around four hours so that it doesn’t take over my life. So, this is how much I study to be able to maintain my pace, and I’m currently at N4 grammar wise (already finished). While I currently don’t have an active subscription, I plan to buy one for one year during February (the reason I don’t wanted to renew it right after my free trial is because I wanted to practice N5 and N4 a bit before moving on).
Now, having WaniKani and Bunpro together appears to be a dream team, and it is… if you pace yourself correctly. In the last week before my trial expired, I had to do more than 100 reviews every single day, additionally to the ones on WaniKani. So, if you go too fast, it will end up consuming most of your time that you use for studying Japanese, and why the heck am I talking about pacing right now if the topic is if you should use WaniKani???
Back to the topic : Is it worth buying WaniKani? This can’t be answered with a simple yes or no, since it has its pros and cons. In general, I would say if you think that the learning style that WaniKani uses suits you, you could try it for a month or two and then see if you still like it. After that, you can still change your mind. But if you choose to use WaniKani, you should always keep in mind to pace yourself correctly so that it doesn’t end up taking away too much time from your Japanese studies.
(This post didn’t end up quite as I’ve imagined, as 50% of the post is about me lol)