A couple of things:

(1) There won't be any Emerald Aisle or full #1 Club Gold service at downtown locations - at least none of the ones I've seen. At busy downtown Hertz locations, there is sometimes a Gold desk (e.g., one end of the counter where a Gold member could go and get served quickly if there was a line).

At most locations there isn't even that, but it isn't necessary because there usually isn't a line and like I mentioned above, Hertz does recognize the status and uses a common computer system at all locations and follows the same rental process everywhere. (At least IME - I've rented off-airport from Hertz dozens of times.)

(2) Rental rates for downtown locations bear little correlation to our usual experiences at airport locations. The good thing with Hertz is that most coupons and discount codes work at off-airport locations. But...the dirt cheap weekend rates usually aren't as low. In most cities, I've found that by playing with promo/coupon codes I could get Hertz rates to come out similar to those at Avis, Budget, etc. Once in a while, a Payless or Enterprise would come up significantly cheaper - then I decide whether it's worth it roll the dice with "Not Exactly" to save some money.

(3) The unfortunate situation that Canarsie describes - a location out of cars in your car class - unfortunately happens more at a downtown location than it does at airports because they might only have a few cars on the lot to begin with. This works in my favor (free upgrade) about ten times as much as it works against me, but I have had to take an occasional downgrade. Hertz has been very apologetic when this has happened and usually changes my rate to something very favorable. (If you are renting a specialty car or truck, you might want to talk to the locations directly to see how sure they are that you will get exactly what you booked.)