https://www.kaiko.com/ seems to the same data but with far longer historical coverage (Tardis starts from April this year). The drawback of Kaiko is the higher price tag.
Yes, kaiko provides similar service and there are others in this space as well, but it's normalized data only and only snapshot of 10% of the top of the order book taken every minute - not streaming order book data (initial snapshot + incremental updates). It works for some use cases, but not all, hence my API which I'd hope fills that niche.