Interesting enough, the mooncake team was building SingleStore before, and so far it is the best production-ready HTAP system. One lesson I really learned is, people don't want to switch their system-of-record OLTP system.
Spoiler-alert: Mooncake will be supporting HTAP use-cases soon, and it comes with better trade-offs: keep your OLTP postgres tables as is, and mooncake adds analytics capacity to those table on up-to-date data.