Topic: MQ and MICS Gas Sensors

[Red Dragon]

I'm wanting to build an environment monitor with an arduino and wanted to add some gas sensors to monitor the air quality. I want to know which sensors should I get. I was looking at the MQ sensors since they seem to be pretty common but I'm also looking at maybe getting the MICS sensors, http://sgx.cdistore.com/
Which one do you guys think I should get to help monitor outdoor air quality?