The system from aquariumplants.com seems expensive since it doesn't come with a CO2 tank, and I don't really like the regulator on the greenleafaquariums.com system, but I have never actually used it. I have the Milwaukee regulator/solenoid. Essentially, I think both "complete" systems cost just as much as putting together your own system. In hindsight, I would have started out with a 20 pound tank in lieu of the 5 pound tank I bought, and am actually debating between a 35 and 50 pound tank at this point.
At the end of the day, I think both systems will work just fine.
