Instruct: Classify the given review into positive or negative sentiment.
Query: buyer beware

exercise caution when dealing with qps products. i have a g4/dual 450 with os 9. the installation cd would not appear on my desktop! this is such a basic function! as reported elsewhere, customer support has been non existent. other mac users have given this unit good reviews but unfortuantely, my experience was quite the opposite.