I recently shipped personal effects and a car from Abu Dhabi by sea in a shared 40' container using a reputable agency. Took a while to clear the port but no damage and no unreasonable charges - just the port & customs costs at actual.
Couple of cartons were damp (it rained that weekend) but contents were OK.

Only problem was black, sooty paw prints all over the car's light coloured leather seats. The sniffer dog in the Port apparently. Not the agent's fault and the marks wiped off with a bottle of leather cleaner.

The assessed value of the car was reasonable. Bit naughty to charge 5% customs again when the duty was paid when it entered UAE. No real cooperation in the GCC !!
Overall things went fairly smoothly - maybe I was lucky?