I have used them to ship a CS80 form California to Ireland and a Prophet 10 from Wisconsin to Ireland (an Ebay auction).
They were recommended to me by an engineer friend who does some work for Def Lepord and Ronnie Wood (on occassion) as they live in Ireland, and they all use Rock-it.
They are expensive - but they are fantastic. The P10 crate was incredible. It was held suspended within the crate by a framework of wooden beams, padded. There was a type of 'once-off spirit level' on the crate to prove that it was not titlted during the entire journey.
As said they are expensive, but what I did with the P10 auction was ask the seller would they mind holding the instrument for another 2 months after I paid for the unit, until I could afford shipping. The seller agreed so I went for their instrument, and because the seller had excellent feedback, I was confident I could leave it with them for that lenght of time. When shipped by Rockit-Cargo, the instrument arrived perfectly.
The CS80 from California also worked perfectly on arrival, pretty amazing when you consider how fragile CS80s can be once moved.
Rock-it cargo are not the only reputable shipping company of course, but they are definitely worth the expense when shipping a very expensive or unique instrument. But if you email them for a quote, brace yourself!!
Kevin.
