Since the null-coalescing operator (??) and the IsNull function appear to do the same thing, I was wondering if there is a performance benefit of using one over the other.

Hello Anil,

The null-coalescing operator ?? should perform a bit faster than the IsNull function, because the functions are resolved via method attributes, which involves reflection, while the ?? operator instantiates a new binary function and passes the operands to it. However, I expect the execution time for both to affect the performance by a very small factor, because the resource-consuming tasks are mainly performed during the process of building the processing tree and rendering the document, so it's much to your preference to use one or another.

Regards,
Ivan Hristov
Progress Telerik