Got it, thanks. The base rate was the same on both so I rented with Hertz in this instance (esp. to be safe to get my 20th rental).
I haven't had Hertz overestimate taxes (that I recall) - though I have used points multiple times in the past at my local outpost, and Hertz has said that I'd be responsible for taxes, but I've paid $0.00 (no taxes or any fees).
Thanks for the help!