With respect to the FM2n being a lot more expensive than an F4, it depends on where you're looking. There's still a black FM2n for $129.50 at Kenmore Camera. Decent looking, everything works well.
With respect to the F4: The F4 is like the Minolta Maxxum cameras of the same era. They do frequently develop LCD bleed, but it seems to be more in relation to impact damage, at least with the lower LCD in the finder. The upper LCD, who knows. If you like manual controls, it's a nice camera. Centerweighted metering pattern is the same as the pattern used on most older Nikon bodies. AF speed isn't bad. The hunting around can get annoying after a while, though. With lithium batteries in the MB-20, AF is useable. With lithium batteries in a MB-21 or MB-23, it's quick. Just not that accurate if there's not enough contrast. Also, there's only one focus point. Meter-wise, I've had one F4 that started grossly underexposing photos (shot Ektar 100, set the ISO at 64 - photos looked like I'd shot them at ISO 400). Possible that something happened between the times I owned the body - was what I call a boomerang body - sold it to a friend, then bought it back when he decided he didn't want it anymore. Traded the camera toward an 85/1.8 K-type Nikkor. Probably a good move. Depending on the cosmetics of the body, I'd say the price is actually on par with FM2/FM2n bodies, provided, you're not buying the latter from a collector who's posting a feeler price on eBay. If you're looking for the 1/250 sync speed and don't care about the rest, just get the body I PM'ed you about. It's a decent FM2n.
With respect to the F5 metering, I've never experienced that issue. That said, for the most part, since I frequently use manual lenses, I'm in centerweighted metering mode. Just switched my F5 back to matrix, since I have a 28-70/3.5-4.5 mounted to it. First 10 frames were centerweighted. We'll see what the last 26 look like.
-J