I have has my 640 since Jan. love it it has cooked great for me. I did not go with the comp. cart but did do the wheel mod. Much better than the stock wheels and left cash in my pocket..cost about 100 bucks. Comp cart does look cool, and may be worth the extra cash if you do lots of contests. For me I would rather have extra cash to buy pellets, or spend it on the second shelf, temp ports or the custom thermal blanket they make for it.