Got the Ultimate Edition of
Stargate most recently. Aside from a little bit of edge enhancement in a few scenes, I thought it was a very nice-looking transfer. I did notice some 'shimmering' during darker scenes, but I think this is to do with the source materials and is not a fault on Optimum's part (as this is a port of Lionsgate's US release).
In any case, it's meant to be a big improvement over the last release, and it's pretty cheap at Amazon -
Stargate [Blu-ray] [1994]: Amazon.co.uk: Kurt Russell, Djimon Hounsou, James Spader, Jaye Davidson, Viveca Lindfors, John Diehl, Alexis Cruz, Leon Rippy, French Stewart, Mili Avital, Roland Emmerich: DVD.