I think the author of Bakku's review is expressing the same frustration that many literary-minded non-academics (and more than a few academics) are experiencing; literary academia has long perpetuated the notion that if a contemporary literary work is popular, then it can't be good literature (and genre literature is straight out). Many scholars of literature don't feel this way at all, but somehow the literary community has continued to give off this sense of what constitutes good and great literature. It has led to a backlash such as what we see in the above review. However, if the above reviewer actually believed what s/he wrote, then that person would walk into the library or bookstore blindfolded and select reading material at random.
Of course we can decide whether or not some literature is better than other literature; we won't agree in every case (e.g., some here think
The Brothers Karamazov is one of the greatest novels ever written while others think it should be prescribed to insomniacs who aren't responding to medication
), but we will agree in most cases.
I agree with yitwail that the longevity of a work should be taken into account; if people continue to read it of their own free will decades, centuries or millennia after it was written, then it's probably a great work of literature (whether you personally like it or not).
Thalion, you get to the heart of what makes great literature great: what does it encompass--does it speak to the universal human experience or provide insights into human nature? Does it make you think? Add to this adept style and technique, and you've got a literary winner.
To sum up this long-winded and rambling post: yes, we can determine what is and isn't great literature with a high degree of agreement. However, with regard to contemporary literature, we must be careful who's doing the labeling.