kermaier
Well-known
the canon 35/2.8 is lovely; as rob says it displays a more "vintage," low contrast look.
You should be able to get a Canon 35/2 for under $600 too, if you need the extra stop of speed.
the summaron 35/2.8 is really nice from f4 down; it's pretty soft wide open imho.
I don't find the Summaron 35/2.8 to be soft wide open -- I have 2 samples, one in M mount and one in LTM (for sale in the RFF classifieds).
But the Summaron 35/2.8 sells for above $600 these days in good condition.
::Ari