The others are all over eBay; just to name 2
http://www.ebay.com/itm/322285148562
http://www.ebay.com/itm/141034024297
Edit: Didn't realize they had the water saver kit. That was one of my biggest concerns with all of this - all the damn wasted water just flushing away..
I personally would absolutely not purchase those. I highly doubt that they are using 150GPD RO Membranes. They are most likely using DOW 75GPD 50PSI membranes but saying that they need to run at 100PSI. Someone in the comments even states don't be upset when you don't get 150GPD.
I also like something that will be so critical, but you should only have to buy once, to have a company that stands behind their product. Buckeye Field Supply, Spectrapure, BRS, among others, are all companies I would purchase from, not necessarily in that order because I have some confidence that they will still be around to help service my equipment in 2-5 years.
Also, I apologize if I came off curt in my first response, that wasn't my intention.
I personally, as long as you are sure you don't have chlorimines, would just spend the $250 on the 150GPD Value now. You get a PSI gauge and a dual input TDI meter along with the water saver kit. I have found each of these useful in the years that I was reefing (I no longer have my 180 and need to update my signature, but I'm getting the itch again). The only reason I wouldn't go this route is if you have very low water pressure in your home, in which case I would forgo the water saver kit and get a booster pump.
https://www.saltwateraquarium.com/puratek-deluxe-100-gpd-automated-4-stage-rodi-system-vertex/
Know anything about this? It seems to have good reviews as well as a 1/1 good/waste water rate..
Is the inline TDS meter "cool" or actually useful? I have a handheld one that I can very quickly tap a button and dip it...
Link to the puratek?
Most of these units use the same Filmtech membrane(75GPD) and try to sell an unknowing user something that just isn't truly possible. If its only 1 RO membrane then they are trying to sell you a 75GPD membrane and push more pressure through it giving you RO breakout(some of the TDS is pushed through the membrane with the increased pressure), and the GPD they advertise. If you can't supply the pressure they are using, its still only a 75GPD membrane. It'd also not good for the membrane to be pushed at such high pressures.
The BRS 150GPD unit uses 2 RO membranes. Basically what this does is push the waste from one RO membrane through another. Effectively giving you 150GPD production.
I've seen buckeyeHydro and spectrapure reps post in a few threads boasting this same thing, and warning end users about this. They are trying to get unknowing users to buy their product and stand out from the rest of the RO/DI manufacturers.
Stick with a well known manufacturer. They will still be around for a few years, and they are typically here on the forums,or you can call them if you have any questions. The others, good luck with customer service should you need any.