If you need a compact platform for PhotoScan, or want the most cost-effective option (performance per dollar, rather than absolute highest performance) this compact dual GPU system is ideal. The high clock speed processor in this system gives the best performance when building meshes and textures, in trade for slightly slower performance with building dense point clouds. As long as you aren't using large image sets or ultra-high quality settings, though, it does quite well.
If you aren't sure how much RAM your photo sets will require to process, here is a chart from Agisoft showing their memory recommendations.