I regret no debt as much as I regret mortgage debt.
If I was as close as you are to paying cash for a house I would wait and pay cash.
If you do decide to mortgage, I couldn't ever get the math to justify doing more than a 20% downpayment, as in, there was never an advantage from an interest rate standpoint and you can always pay more per payment if you want to, little advantage to limiting your options.
Within 3 months of buying all my houses I have had some massive catastrophe befall me which used up all of my remaining cash, which is either an argument for or against having extra cash on hand afterwards, depending on how you look at it.
I've heard it described as a 1 year involuntary vow of poverty.