I have been doing Milesource for about a year now. I have cashed out for Supercertificates several times with no problem. It does take a while after you get the confirmation email before you get the actual email that contatin your Supercert. I usually have to wait about a month for that. I think Milesource probably sends their redemptions to Giftcertificate.com once a month. I'm not positive of this, but that's what it seems like based on my experience with them. Once I go on line and redeem my Supercert, I usually have the paper GC's I order within a week or so.
I just looked at my records & saw that I last cashed out at Milesource on 2/21. I had the paper GC I ordered in my mailbox for TGIFridays by the last week in March. I usually redeem for restaurant GC's, some of which we use near our home. I've always been very happy with them. I hope your experience with them turns out to be as good as mine has been.