Had to cut some 1/4" metal angle iron to allow for sink clearance. In the past, we have had trouble because our metal cutting jig saw blades just wouldn't work that well.

I found some jig saw blades that would do the trick.  In fact they cut through the steel better than my other blades cut through solid surface.

thats my brand of choice too.   I use those blades to rough out the sink and cook top holes with the same blade.