I'd say it boils down to personal preference, how you feel about the look of the Spied. I love the look of the them and can't wait to try to make some myself. http://ball-pythons.net/forums/showt...pider-het-Pied
The pairing can lead to Spieds, Pieds, Spiders het for Pied and normals het for Pied. I personally believe that is a strong pairing buisness wise.
To give you an idea of what Spied prices are right now you can check out Steve Roussis's websitehttp://www.roussisreptiles.com/available.html Just remember these prices will likely decrease by time you'd possibly see a Spied head peaking out of an egg.

Another thing I feel is important is you've got to really trust the person selling the Spider as het for Pied. There is no way of telling if it's really is het unless you spend years raising her and then breeding her to prove her out. Which can be a big waste of time and money if she proves not to be really het.