ASP/VBScript style question (functions)

[Strogian]

Function bob(input)
Dim string
For Each string In input.Strings
bob = bob & string
Next
End Function
 
Function bob(input)
Dim string, finalstring
For Each string In input.Strings
finalstring = finalstring & string
Next
bob = finalstring
End Function

Which one is better? My C background makes me want to do the second one, but what is more natural in ASP/VBScript? My concern is that just saying "bob = bob & string" might be slower than "finalstring = finalstring & string", similar to how 'Session("bob") = Session("bob") & string' would be slower.