The Pentax LX is an excellent manual focus film camera that provides outstanding stability and performance. There is however some pitfalls when buying a Pentax LX that should be observed:

Shutter/mirror:
Older cameras tend to suffer from the mirror sticking on the first exposure after periods of non-use. This is due to rubber parts deterioating from old age. This is fixed with a standard service ($100-$150).

Exposure system:
One fault is that the exposure meter does not turn off after use, or that it turns on and off without user interaction. This will drain batteries in no time and might render your exposure system useless at a critical moment. Be sure to check that the exposure LEDs in the viewfinder turn off automatically ca. 25 seconds after activation. The repair for this fault is an expensive circuit board replacement.

Some cameras also show unconsistent exposures in the 800-3200 ISO range. The reason for this fault is as far as I know unknown.