They are both nice subs. I would ignore the comments about the ported design. I believe it is more a problem with the operator not knowing how to setup an integrate the sub. The ported design enables the Storm to go deeper than the Stratus. Do not assume that the persons posting reviews on places like Audioreview and the like know what they are doing. Most of the subs higher up the ladder than the Storm are also ported. Someone made the same comments about port noise in the Stadium. If you want two subs, one better one is usually better than two cheaper ones. Especially since you can always add the second one later when your budget allows.
The way to tighten up the bass in the Storm if you feel it is needed is to replace the stock power cord with something better (2 meter cord). Happy listening.