In my mind THE function that MS have FINALLY added that they should have added a long, long, long time ago is IFERROR, previously you had to double evaluate else use a UDF to avoid, the IFERROR is essentially the UDF we've all probably coded which namely evaluates result of a formula and returns an alternate value if the result is an Error value.
Before:
=IF(ISNA(MATCH("Test",A1:A4,0)),"Error",MATCH("Test",A1:A4,0))
Now:
=IFERROR(MATCH("Test",A1:A4,0),"Error")