If those are your choices, and you're using it on an FE, in my opinion, it's a no-brainer to go with the Nikkor 35mm/1.4 AIS.
Advantages for the Nikon lens: it goes to 1.4 if you need it; maybe not as sharp at F2, but beyond that it'll rival the Zeiss in practical terms for sharpness; smaller; lighter; takes a 52mm filter like the vast majority of Nikon's MF lenses; it's way cheaper (second-hand at least); it's a lot more "stealth" and non-threatening for street shooting than the Zeiss; build quality is probably better (I own the Nikkor, never have owned/used the Zeiss); it probably balances a lot better on your FE, it should fit that camera like they were originally made together to complement each other.
The Zeiss, in my opinion and based on what little I know of it, probably has a single advantage: it likely *is* sharper than the Nikon, especially at F2 and maybe 2.8. But if you're using it on film, are you going to actually *see* any differences? Particularly if you're not getting high quality scans of color transparency film shot on a tripod? If you're shooting either lens street-style on 400 speed black and white film, I really can't imagine someone looking at the negatives/prints and going "Ooooo, those were shot with a Zeiss!" Let's be real. And particularly because when stopped down a little, the 35/1.4 AIS is *very* sharp indeed.
I once read a review by an actual user of that lens who said it was the best lens he'd ever had at rendering complex textures. I don't know about that, but from F4 to F8, mine gives fantastic detail--and it's no slouch at 2.8 and for some things at F2, either.
I'd go with speed, size (small), and overall "harmony" and, errr, "gemütlichkeit" of using a Nikon lens on one of Nikon's smallest (but most capable) cameras. I own the FE (two of 'em, one in chrome, one in black--as you should) and the 35/1.4 AIS, and that is indeed a very, very happy combination for walking around all day with and being "in the moment." And bringing back some images no one could possibly complain about in terms of technical quality.