I have an 'ARB-style' full length mesh rack, and can concur with all of the above - seriously heavy, so do some GVM calculations. Hard to wash under it. Impossible to get into low carparks/garages. Wind noise. But boy do we miss it when it is off the car... it's a brilliant place to throw bikes (we have five to carry) and other big or bulky items, the kids love sitting on it, and with a side and rear awning on it, wherever we stop we can have shade. I have a full length Southern Cross canvas roofbag and can carry a huge amount of (not too heavy) stuff up there with this set-up.
A tip for anyone buying a Chinese rack - before you commit, find out how many bolts are in the fitting kit, and the sizes, and then price decent quality replacements. You will have to replace them unless you are ok about rust stains on your paintwork, and it only takes a couple of weeks for the cheap bolts to start rusting. The cost of replacing the bolts might make that bargain rack look a little less like a bargain.
The paint/powdercoat on mine is also not nearly as good as ARBs and eventually the whole rack will require attacking with rust converter and new paint. But overall it seems to be fairly well constructed.
I also have a set of aero-style bars and a Thule roof pod, which is another good way to carry gear; you just can't carry as much. Certainly a lot lighter and easier to manage than the big rack... and lockable/waterproof too.
