First thing you should do is get a copy of the water quality report from your water district, assuming you are not on well water. This will tell you what they are putting in the water. If they are using chlorine then a regular 4 state unit will most likely work. If they are using chloramines then you will most likely want a unit that includes a carbon filter made to remove chloramines. As for which unit, that is up to you. Most of the name brands from one of the sponsors are good. I personally went with Spectrapure because I have high tds. My tds is usually around 450 and their RO membrane gets it down to 3 or 4 before it goes into the di filter. As stated, if you have good water pressure you want have to wait around all day for water. I can fill a 5 gallon jug in about 1 hour in the summer and it takes about 80 minutes in the winter. As long as you don't go with a proprietary system the RO Buddy that requires you to buy their filters, you have a lot more choices in your filters since they are all the same size. I prefer to use better filters so I go with a .2 micron sediment filter and a .5 carbon filter. Most budget systems come with 5 micron.
Another great reason to go with a regular ro system is you can easily expand it as your needs change. If you get a larger tank and need to make water faster you can add another ro membrane to increase the output.
