Yes, it works!
We also use VGA to HDMI converters and also DisplayPort to HDMI. The converters may require their own power supply (USB or PowerSupply) to provide the required HDMI signal to the Optoma transmitter. The transmission quality and reliability of the Optoma WHD200 is excellent.
Please use high quality HDMI connection cables and connectors. This is the only weak point of the system found so far, the HDMI connectors! If you take care here, you will have great pleasure in the product.