Taken as a whole the HHR SS (couldn't they have just named it "Sport")? is a big step ahead from the normal model.
Still, while the review from the outset has a negative overtone, it's just compltely without reason. Facts are facts and compared with the MazdaSpeed3 it doesn't turn as sharply, the steering is not as crisp and natural, its suspension isn't as good, and it doesn't handle as well. It's not OMG T3H BIAS!!11 either...it's common sense. The Mazda has a more advanced suspension, isn't stuck with electric steering, has a lower center a gravity, and so on. MazdaSpeed3 simply had a better, more advanced vehicle to start with. Chevy had a less advanced vehicle.
Ocn, you seem to be grabbing at straws. The MazdaSpeed6 is coming back with the next generation..it's not uncommon for trim levels to start to disappear shortly before a model is redesigned...look at the Vibe for example.
As for the PT bashing, the PT, despite being older, has come out ahead in comparison tests, and has been noted for having a better interior with more personality (although I hate the seats, far too narrow for me).
Overall I'd say that that the HRR SS is pretty good...it's probably not as hardcore as the SRT4 or the 3, which will attract some buyers. The SRT4 is a monster for those who want one, and the 3 is the sharpest and most dedicated sport hatch.
edmunds review is unnecessarily harsh yes, but at the same time valid points, both good and bad, are brought up.