Does anyone use both steel alloy and nickel silver EZ track and if so does it work just fine or are there some mishaps?
They will go together fine, but you don't want to do it. go with all NS.
I will add this: don't buy anymore steel track, if you buy more track, buy the NS. What steel track you have, you may want to consider, if you have the opportunity, to use it for sidings where conductivity and clean rails matter less and use the NS for sections of the layout you constantly run trains.
That's what I was thinking too I plan to use all NS tracksince I recently got the Echo Valley Express the other day, but I also plan to ask for the thoroughbred train set for Christmas, since it comes with SA track I was just wondering if they would go great together.