Low Profile HVAC vs Mini-Split Cost & Advice

Hi,
We just bought an Eichler home in Palo Alto which has ceiling radiant heat but no A/C. We are trying to understand the cost and performance difference between Low Profile HVAC vs Mini-Split. We were able to get one quote for mini-split for the whole house (6 units) at 24K but having really hard time finding information about the low profile roof HVAC. The roof of the house needs changing pretty soon as well. 
I would truly appreciate your input if you have had installed one or another, why did you choose the one you have, what was the cost difference, what would you do different, what you wish you knew beforehand. And of course, if you have a provider recommendation.
Best Regards,