Honestly, there are four or five makers of the actual components of RO/DI units. After that, there are like 100 distributors and companies like Kent, Spectra-Pure etc. I purchased my unit from here (www.buckeyefieldsupply) and it has outperformed my kent and oceanus RO/DI. This guy is a cincy local, and i wish I would have bought his 4 stage unit much earlier. He sells his for 1/2 the price of the competition while using superior parts.
Email for pics or any more questions.
Craig
YEp, finding the 'best' anything in reefing is problematic. RODI is pretty straight forward, and its kinda hard to go wrong. Buy from someone reputable, and get the right system for your needs.
any power seller on ebay with >1000 listed transactions and >99.0% positive feedback will usually be fine. the price is very competitive -- not too low to believe but still a good buy.