I just started using Renshuu for grammar. I did the free trial for BunPro sometime last year, but I liked the grammar resource I was using at the time, so I didn’t sign up. Both services seem pretty similar in how they test grammar, but Renshuu includes lessons. Renshuu also seems to have vocab and kanji (although I haven’t checked either out since I have lifetime with WK) and the kanji seems to go beyond what WK offers.
As far as price goes, Renshuu has twice the subscription costs, but a cheaper lifetime and more games/types of practices.
Has anyone tried both? Do you have a preference for one or the other? Why?