This used to work in Leo, no more in Snow (infinite loop):
set mySize to "missing value"
repeat while mySize is "missing value"
    tell application "Finder" to set mySize to (size of alias myFolder)
end repeat

(the repeat loop was necessary because just asking once returns 
"missing value" but looping produces a number).

In Snow Leopard I now must use
set mySize to "missing value"
repeat while mySize is "missing value"
    set sourceSize to (size of (info for (POSIX path of myFolder)))
end repeat

This does the job, but the Scripting Additions dictionary says that 
"info for" is deprecated, and one should tell System Events to get 
this record. But when I tried that, I could never get it to produce 
anything but "missing value", with the loop inside of or outside the 
tell block, so I'm stuck using the deprecated call.

Does anyone have any insight in this (with only vanilla osaxen)? TIA.