I have purchased three of them off E Bay and haven't gotten a bad one yet.
By all means check the wind mechanism for wear and make sure it operates smoothly.
I haven't yet found any problem with oil on the shutter leaves, but I have had to clean the back side of the lens and the mirror will probably need to be cleaned. One other word of caution, it you are going to use the self timer mechanism make sure the flash sync. lever set to the X position. If you try using the self timer in the M mode the shutter will jamb.