Is it better for me to use the 301 redirects... that way I don't loose all of my redirect entries if the standard SEF URLs get purged and have not been locked? The aliases get lost during a purge, correct?

Perfect! That worked.
CV

Again, I have built a replacement site in Joomla and the old one was a ".NET" e-comm package. So all of the pages end in the extension ".aspx". This might have something to do with the ".htaccess" file as well?

Here's one example:

Old:
/c-10-34-inch-thick-round-glass-table-tops.aspx

New:
/shop/round-glass-table-tops/3-4-inch-thick-round-glass

Thanks,
CV

I have build a new e-com site for a client and need to create some redirects of the old URLs to the new ones. Can I use an "alias"? I tried to enter one... but I just get an Apache 404 error.