Seems like every day more and more ASIC devices are being created for various algorithms. But with SIACoin, that might be a downhill battle when they are released since the algorithm is so unique to SIA. Unlike other ASIC devices that could mine other coins with a similar algorithm, ASIC devices for SIA will most likely reach a dead-end much sooner than other ASIC devices.
But then again, who knows. It might be a great success for those that get into ASIC mining SIACoins, but then again that will put off people like myself that are mining the coins with GPUs while mining Ethereum (or other coins that are capable to be dual mined).