I own a F2AS, F3nonHP, F3HP, and a F3P.
The waist level finder is impractical on a F2 because you loose metering.
I find on a F3 a DA-2 Action Finder to be very stealthful with a 24/2.0 ultra wide. Aperature priority is there if I need it, but is seldom used. I mostly shoot zone focus at f 5.6, after metering off the back of my hand. I also shoot a lot from the chest with this rig.
My F2AS is almost as heavy as an F3 with a motor drive. F2's are extreamly overbuilt cameras, but a heavy camera, in my opinion, is a steady camera for available light/hand held. The LED's of the F2AS and F2SB make the meter night friendly and the metering goes lower than the F3's.
The ultimate night rig is a F2AS with a 58/1.2 Noct AIS (AIS has a 9 blade diaphram and faster focus over a 58/1.2 AI). For night and extream low lighting the F2AS and F2SB are "unbeatable."
The F3, although not a mechanical camera, is very robust. Don't be fooled by cheap prices that are due to its former popularity, long production run, and durability that has created a bargain. Most recently I bought my F3 nonHP for $200.00 in excelent condition with a motor drive.
The F3 has the smoothest winding because of bearings. To me the F3 is the most and best engineered camera Nikon ever made. Be aware that because I have a F3 collection I have determined that the non HP finder (the cheapest) has the best focusing for both dim lighting and when used with telephotos. Although the HP finder projects a larger image, the smaller image from a nonHP finder indicates more detail and contrast, especially under adverse dim lighting and with longer lenses.
Also be aware any F2 or F3 is likely to need new light and mirror foam seals replaced.
Good Luck.
Calzone