searching for analog-to-ADAT- and ADAT-to-analog-converter

i need more OUTs/INs for my MOTU 828mk II.
so i wanna buy an analog-to-ADAT- and ADAT-to-analog-converter (each 8 channels)!
somebody told me the RME ADI-8 PRO is a good choice. is it?
are there other alternatives? maybe cheaper with the same quality ;-)

THANX in advance for your tips!