If the investment is doable and you have reliable advice on what system to get, then I say go with pressurized from the start. But...DIY was a great way for me to be introduced. It's cheap, the citric acid method worked surprisingly well, and it gave me time to research regulators. That being said, I'm looking forward to not having to monitor and tweak my CO2 setup nearly as much. Pressurized cost a lot more up front. So if DIY will get you started and excited about aquascaping, then go for it. You can always upgrade.