About ten days ago I decided to replace my 10 year old Culligan reverse
osmosis system (that costs $20/mo and is close to 10 years old now)with
something modern hopefully better and cheaper. My only issues with the
current system are the monthly charges and water flow rates a bit less
than I would like. After 10 days of surfing, googling, reading ebay ads
and other web sites I am almost ready to buy.

If there is a good place on the web to fully discuss Water filtration
and reverse osmosis systems, I have yet to find it. Many sites are good
but limited, Waternet.com for example has a forum for water treatment
professionals that seem happy enought to split any technical hairs
brought up, but they don't like to talk about who makes a good product
or who sells it cheap. Other sites do well in explaining all the nuts
and bolts. I am posting here to get a few consumer issues out in the
open, and get some experienced comments.

Good.
Reverse osmosis water systems are now a mature technology, and good
systems are fairly cheap and easy to install. A basic system consists
of two or three filter bodies that accept a variety of standard sized
10" filters, the RO membrane, a storage tank, and the various plumbing
bits to hook up to the cold water line and the drain, plus a faucet if
desired (I just use the fridge for now). Three extra goodies are worth
talking about, permeate pump, watergap faucet, and a disposal drain.

Aquatec makes the Permeate Pump, visit them if you want more detail,
but the important bit is that it costs about $70, and is powered by the
pressure difference between the waste outlet of the RO unit (house
water pressure) and the drain (no pressure)and pumps the RO water into
the storage tank. This does three really good things; storage tank
pressure is close to house water pressure (about double a regular
system), RO membrane differential pressure also about double (better
filtering, higher flow rates), less waste water down the drain (mostly
due to filter flow).

Watergap is made by Arrowhead Brass, and its a kinda pricey faucet ($50
to $100 about), but it combines a water filter faucet with a dishwasher
airgap so you don't need to drill a hole in the sink to use get
filtered water. Has me dancing in circles, one caveat, current
production is suppose to work fine with a RO unit, but older units that
some net sellers have say don't use on RO.

http://www.ecotech-dla.com/dla-d.htm makes a $6 universal drain line
adapter that may be easier to install in the dishwasher to garbage
disposal line than the older saddle adapter to a drain pipe.

Bad.
Price and quality information doesn't seem to exist. Ebay is cheapest,
local "water" professionals maybe the highest, and indeed what you
"need" may vary a LOT depending on local water conditions, especially
well water that has a high level of something you want removed like
iron (really just means one more filter body with some kind of resin
bed like a water softener uses sort of). Even with a lot of items
normalized, connector choices and the plumbing adapters can shift the
price a LOT, some maybe easier to use, or more durable, but the only
discussion I see are from vendors selling their own stuff. Hopefully
some of you here will have some suggestions. Lacking that Costco sells
a system by Watt with a permeate filter for about $270, and is great if
anything ever goes wrong.

Ugly.
I just know somebody is going to try and drag this thread into a
pointless discussion on the merits or lack of drinking RO water.

Zero waste.
I wrangled with this and decided against zero waste. Permeate pump and
a AC booster pump cost about the same to buy, with likely a lower
lifetime cost on the permeate pump since its a pretty simple device and
uses no power. Issues to me are 10 gals or so a day of waste water, vs
no extra AC outlet handy under the sink, and perhaps false concerns
about pumping 10 or so gal per day of cold water down the hot water
line to the water heater, and the same amount of hot water out of the
water heater into the cold line (its a loop). This is exactly opposite
to the trick of putting a pump with a thermal switch on the farthest
faucet that pumps water from the hot to the cold line, so that water
doesn't go down the drain while you wait for hot water to come out.

Thanks for your help, and I hope some good info gets into this thread.