Fomapan 100 (Arista.EDU Ultra 100 in the US) is a worthy replacement of APX100, although not quite the same in a number of ways:
- the base is blueish polyester (but it lays flat, no worries there),
- contrast runs off quickly with overdevelopment,
- not as mechanically tough or reliable as APX (I had problems with 'micro-scratches').
Contrast can be controlled well (try Rodinal).
The two films share the same 'old-fashioned' look, to my eyes at least. If it wasn't for the mechanical quality I'd be all over Foma 100-120.
These were taken in the winter sun of January 2010, and one inside, of my hat (@ EI 80, Rodinal 1+50, 7', 20 deg. C, H'blad w/ 80 CT*):