[johnklos]

Email aliases don't work any longer, since super smart companies like Google and Microsoft will treat any forwarded spam as original spam and will then consider the forwarding server to be a spam server.

Not sure that this is actually forwarding, but with no way to find out except using it, I'm just going to guess that it is based on the description on the site.

[connorpeters]

It's not actually forwarding, it's sending a new email with the same content. I haven't seen any issues with them going to spam but definitely a concern of mine.