It seems like it would be easy to answer the simple questions asked by Marcus above.
...unless there is reason those 'haters' are correct. Lots of MtGox people used similar arguments when people challenged their solvency.
Did Phinn ever get his 1000 BTC returned?
Unless BTC-Central Paymium is running fractional reserve they should have no problem demonstrating the exact status of their solvency and the Instawallet coins using the blockchain.
As has already been done recently by other reputable, transparent exchanges in wake of Mt. Gox debacle.