Well the blame for the Zenith can be laid squarely at Mr Jay Javier's door - he has one on his site and I saw it and just knew I'd have to have one! Yes, it's one sweet camera, sort of honorary RF I think.
The FED 4 hasn't been used yet - I have several other cameras in the queue to be used first! I think I perceive the rewind issue though. It needed the VF/RF cleaning but otherwise seems good. The FED 5B is an olympic version and needs new curtains, otherwise in excellent condition (possibly *because* of the curtains!). Both needed the lenses re-lubing, unsurprisingly. The 5B is a little project for a rainy day I think...
To be honest I'm not keen on the looks of the 4 or 5, but I needed them to complete the collection of major FED models. Having said that, they are growing on me and the 4 seems to be a very good "user", plus they were both very cheap.