I’d have to agree here. Without a discount lifetime will equal ~2.5 years of monthly, well past the average time to finish. Skritter and Satori Reader are also pretty expensive for services with similar appeal, but I think all of them are worth if someone can afford them. Like you suggested, I’d still recommend a textbook or something else instead if money is tight.
As for my WK experience it has been nothing but wonderful. Somewhere around lvl 15 I hit up the beginner grammar textbooks hard and have had almost no problems with the kanji in them. Around 25 I started trying to make it a regular habit to read NHK Easy News and have been having a much, much easier time getting through it. I don’t really feel like kanji is a weakness anymore, just my general vocabulary and grammar. Even then I don’t feel bad since it’s much easier to read and learn those things on my own now.
My biggest issues right now are that I want to spend too much time on WK over other materials and that I’m not sure if I want to power through the rest of WK or take a break later to focus on intermediate texts. I’ve said it before, but WK is a soul sucking addiction I don’t want to let go.