RO unit?

I am about to buy an RO unit for one of my grows. The water has an ec of 1.0 and it has 94ppm of sodium. Nasty. Information obtained from water company.
I wanted to know the difference between the cheaper ones and the nicer ones you can buy at the hydro store.
I was looking into this one:
4ST. PORTABLE REVERSE OSMOSIS WATER FILTER SYSTEM 50GPD - eBay (item 280484754649 end time May-25-10 11:07:49 PDT)

Do you think this one would be ok? if not why?
Or should I spend the money on a nice one?
recomendations?
thanks

the only thing i dont like about it is its 50gpd. 50gpd means it will only run that if your water pressure is optimal. i have a 100gpd and wish i woulda gone with the 150. but ro membranes are all interchangeable the 50-150gpd. other than that its perfect for what you want it for. you can always customize it with more filters if you want but those are good enough. the other filters you see are just for taste.

Thanks a bunch, I owe you some rep. I need to spread some. The water from the faucet is comming out very strong so I think I might try it out especially since you can upgrade.

I got the 150 from this place.
portable countertop reverse osmosis drinking water system - remove fluoride, chemicals, pharmaceuticals, prescription drugs and more

I love it and can take it anywhere.
Either way your making a ggod choice.

More than anything research the cost of replacement filters and availability.