from memory the premium is the older model and has been cloned by the chinese you can get a clone model from china a lot cheaper than that
you can add a dvbt tuner to it but NOT a dvbs sat tuner as a complete motherboard upgrade was needed hense the launch of the newer premium plus version which will take either
from what i have read support is not up to much but getting better for the newer plus models with some enigma images available
i thing they can be a client box but can not be used for resharing
they have good media functions and can decrypt 4.2.2 feeds
hope this helps