I have used Mojo quite a bit. It’s fantastic and lives up to every claim it makes. When the compiler becomes open source I fully expect it to really start taking off for data science.

Modular also has its paid platform for serving models called Max. I’ve not used that but heard good things.

I’ve also been curious to see actual users compare/contrast their experiences with other options, but so far haven’t seen that.

There seem to be enthusiasts who have experimented a bit and like what they see but I haven’t seen much else.