k12 Fast Start - should we actually use it?

I'm seeing inconsistencies around the k12 platform - that it isn't ready yet and we should use HEDA until k12 is complete vs that it is ready and available with the k12 Fast Start with NPSP/HEDA elements https://www.salesforce.org/trial/k12/

Is k12 Fast Start actually ready for general use?  The non-NPSP packages are unmanaged, which is a little concerning - especially if it is still under development.

I have a client that is moving to salesforce this month or next, and I don't want to get them all set up with K12 if it isn't ready yet...and HEDA is just too much for them.