With double sided tape both the work piece and the spoil board needs to be perfectly flat and smooth to insure complete adhesion. If one is just a tiny bit bowed or warped you may not get a a true solid bond and the work piece may come loose. The bigger the work piece the more of a problem this can be. (How many of you are working with a 100% smooth spoil board with no cut marks?) When using masking tape on each side and superglue in-between the tape can actually fill minor gaps and deliver a solid connection.
I have used double sided tape with mixed results - sometimes it works well and other time not so much. I will say the bond with it is nowhere near as strong as the tape/superglue combo. If you apply the tape and then use a small (1" wide) roller to press it to the surface the bond is greatly increased. The superglue ties them together and when the carve is finished you will need to use a putty knife to work under all the edges to pry it loose. Usually takes a little time as it is stuck well. In fact, on thin stock I donāt roll the tape just press it down with my fingers. If rolled it sticks so well it is easy to break the piece trying to get it off the spoil board.
Also, clean up is a snap as the tape can be peeled off with no remaining residue. Double stick tape can sometimes be a pain to remove completely.
One other plus, it it raises the work piece a little off the spoil board. If you have you depth set correctly you can cut completely through the work piece and a layer of the tape but never touch the spoil board.
I suggest you try the masking tape / superglue method. I think you will be surprised how easy and well it works.