Nickel vs Copper based anti-seize

The Rotax MMH (for 912 etc) specifies Loctite (copper-based) anti-seize compounds for coating the exhaust system couplings, flanges, and mounting bolts etc.  But it seems nickel-based compounds are kinder to stainless steel at elevated temperatures.  I am interested in any experiences and/or opinions on this.  In particular the appropriate compound for coating the exhaust manifold pipe where it enters into the aluminium cylinder block.