my only response to that is that just because it has a faster processor and more ram doesn't mean it will perform better. it all comes down to how good the raid controller is. both products use a software raid controller, i believe. i have finally found some measurements of throughput for the qnap that seem to put it in the same league as the thecus in terms of speed. but the qnap test results are published by qnap, not an independent lab, and they're still lower than the results published by an independent review of the thecus. so it would appear that the thecus has a better raid controller.
furthermore, the thecus does raid 10, which has become the defacto standard for enterprise database applications. the qnap does not do raid 10, which strikes me as somewhat behind the curve. the thecus is also stackable. and a fully loaded n8800 will cost several hudred dollars less than a similarly configured ts-809u-rp.
tough choice.