I couldn't find anything specific for VBA but as far as I checked the answers (for other languages) in VBA this code
If A then B else C
is essentially the same as
IIf(A,B,C)
The only difference is that the IIF-function is a little more compact. I tested the performance, there is no significant change there either. Did I miss anything?
Edit: thanks to whoever posted the link to the VB6 question in the comments. Although VB6 and VBA are very similar they are still two separate implementations and they do not work "exactly" in the same way. In my opinion, this question should be left open since it specifically applies to VBA and not VB6 (but so far I didn't find any differences for the IIF implementation).