Lots of really good subwoofers don't have their "speakers" protected. See - SVS, HSU etc.
Apart from that, however, it's hard to really tell from the review whether they're any good. The only comment about comparative sound quality seems to be "it isnít as loud as my home stereo" which isn't particularly helpful, since we have no idea what your home stereo is, and "loud" is hardly that important in this day and age.
Include more comparisons like that, perhaps?