It's nearly 40 years since I used one, but my recollection is completely in line with Lee's statements, the Focomat is very solid and easy to use. Personally I wouldn't worry about using the Multigrade below-lens filter kit, I have not noticed any image degradation and it allows split-grade printing etc., which is really difficult if you're having to open up the lamphouse to change filters. Don't pay too much for the enlarger, though, they're not too popular these days because of the lack of filter drawer/head.
Regards,
David