I am sure there are hundreds of posts about the SOG system, in fact I know there are I must have read most of them. I have a Thetford C-250S cassette fitted in a Rapido with a double floor. The question I need answering is: Thetford vent as efficient as the SOG? What's the difference between the SOG system and the Thetford vent kit? Is the What are the advantages/disadvantages for either system. Should I be fitting a Thetford vent or a SOG? I'm not interested in messing around with a computer fan and doing a DIY job although I am sure they work fine, I just want to fit the best branded kit. Thanks