I got this one from Filterdirect.com in California for $160.

It has the reservoir tank that keeps the system pressurized and even pushed RO clean water to a faucet upstairs and the icemaker. RO ice is worth it in the long haul IMO, but it'll fill your ATO reservoir a lot quicker if you ever run too much out of your drain.

6100di2 - What RODI unit do you use?