If you have $2000US and you want to get a good, but difficult to use juicer, then the Norwalk juicer is what you want. However, there are many cancer success stories with the modern low-speed masticating juicers (which did not exist in Gerson's time). The Gerson Institute recomends the CHampion if you can't afford the Norwalk, but even that info is out-dated. I have read that the Champion tends to overheat the juice. You will no have this problem with either the Omega or the GreenStar.
So, if you want to get an excellent juicer at a price that is more affordable, then get a GreenStar or an Omega. I don't know about the Omega, but the GreenStar is excellent. 2Tuff recomends the Omega, and I do not think that you will have problems with either juicer. Get the one that is cheaper or more readily available in the UK.