The colours aren't great, it's a bit sensitive to pressure on the bed, but I'm used to it.
For me the command is:
scanimage --device "hp:libusb:001:002" --mode Color --format=png > scan.png
to scan in colour. I've made some bash scripts to easily scan in colour or greyscale. Could do the same with aliases too. Better yet would be one that checks the device and puts that into the command. The numbers will change depending o nwhich USB port it's plugged in to.