I have Blast and like it. Never seen DK. I think lots of the metrics are the same, just different apps. There should be a list of both devices metrics. Maybe check in on how much the subscription is for both, if you want extra metrics. Blast is $60 (player) or $100 (coach) for a year.
I have the dk just because it is used in conjunction with the win reality system I use it mostly to show the actual swing plane I like how you can move around the image like it’s 3D to see the view from front back side or from above once the win reality system figures out how to get dk swing plane into its metrics it will be a game changer. Blast doesn’t work with win reality