Coalesce vs Case

I prefer to use COALESCE over CASE. and the most interesting is the code is much shorter than using CASE.

In some circumstances, ISNULL is faster than CASE or COALESCE. However, if cross platform compatibility is an issue, COALESCE is ANSI standard.

COALESCE() is literally shorthand for a CASE statement, they will perform identically.

However, as podiluska mentioned, ISNULL() can be occasionally faster than a CASE statement, but it's likely to be a miniscule increase as these functions are very unlikely to bottleneck your procedure.

Read here more about the performance differences.