I used 23andMe, and was a happy customer, but asked them to delete my data after -- I wasn't comfortable with them keeping that information (on a long enough timescale, everyone is hacked... or there may be regulatory issues with health insurance one day etc.)

I do wonder if they really deleted my data though?

Would pay 10x what 23andMe asks for a similar service if they gave you only an offline copy of your data, didn't store it on their servers, but also an offline app to analyze your results. There are some open source solutions[0] out there but they're not as user friendly yet.

[0] https://github.com/mentatpsi/OSGenome, https://www.snpedia.com