The F3 has a very smooth and light film wind. LCD in the finder is small, so a little hard to read, especially when metering manually. A nice feel, good balance, good ergos. A tough machine, electronics are very reliable. Many very old ones are still going fine.
Make sure it has the cover on the bottom under the film cartridge compartment, which is removed to fit a motor drive. I priced a replacement for mine, and it was $25-30. If it's missing it might be stored in the end of the motor drive, if that's around.
I taped a dime over the opening and didn't sweat it. My (ahem) out of pocket expense: 10 cents.
One thing: the meter illumination switch, with a tiny red button on the right side of the finder, had to have been designed after a lunch where too much sake was consumed. It often doesn't work or works intermittently; even when it does, it has no feel. I would not reject an otherwise good F3 if it doesn't function properly, another is likely no better.