I would agree with everything @oreodisaster has said. I also started out with KaniWani (probably after reading that same guide), and didn’t discover KameSame until much later. By that time I had invested quite a bit of time and effort to KW, so I’ve stayed with it. I agree that KameSame has some advantages, and I think someday I might return to it.
For now, I like the comfort of the KW interface, which is very similar to WaniKani. You just have to realize that the synonym thing is a problem with KW, but once you learn how to enter synonyms, it is quick and easy and hasn’t really been that big of a deal for me. Maybe I’m kidding myself, but I’m convinced that it has helped me to make some vocabulary connections I might not have otherwise.
You also have to be careful not to take on too much SRS, or burnout can be a real potential issue. I’m pretty efficient and clear my reviews daily, but between WK and KW, it’s not unusual for me to have 250-300 reviews some days.
I’ve stuck with it because I think learning the English-to-Japanese is an important skill, especially if one expects to speak this language with any degree of fluency. As much as I like WaniKani, it doesn’t help much with that.