The proximity question is probably the next most important.... do you want to be closer to water and GG Bridge views, or closer to a South Bay commute? Noe does also feel like a "small" town compared to Pacific Heights, and while they both have a lot of baby strollers, I'd call Noe a "young couple" neighborhood more so than Pacific Heights largely due to the price difference in Single Family homes in the two neighborhoods.
Pacific Heights is a more sophisticated area. Besides Fillmore Street, shopping/restaurant areas normally included in "Pacific Heights" are actually in other areas - Union Street (Cow Hollow), Chestnut Street (Marina), Laurel Village (border of Presidio Heights & Laurel Heights). There are high rise condo and apartment buildings with doormen/security. Homes are often larger and usually more expensive.
Noe Valley is a more "laid-back" area. The main shopping/restaurant area is on 24th Street. (But Noe Valley is an easy drive to West Portal and Stonestown for more shops/restaurants.) There are homes and condos and apartments -- but no high rises or doorman complexes. Over the years, Noe Valley has been gentrified and become a very popular place to live. Prices have risen to meet the demands.
Both areas experience sun as well as fog. Pacific Heights on the whole is probably foggier. Parking is tough in both areas unless you buy a place with a garage (something I highly recommend.)
Both Pacific Heights and Noe Valley are popular places to live. It is easier to commute to the South Bay from Noe Valley. But both have easy access to Downtown and The Financial District.
I hope this is helpful. Please contact me if you would like more information.