1st Owner Finance Deal- is 5% 20 yr am, 10 yr balloon good?

[Jack Tucker]

 OK... been doing lots of cash deals, but never have bought an owner finance deal.

I have found a quad at a good price.

He prefers to owner-finance the deal for $75k at 5% fixed interest, 20 year am with a balloon at 10 years in the amount of $46,666.14.  

First question... is this a good set of terms?  It sounds competitive with my banks.

Second question... This thing gets gross rent at $1620 with upside on market rent. Quick math says approx $645 PITI.