Hi, I've used JRA Wheel Milk and Stan's NoTubes "The Solution" for ages on several ghetto tubeless setups. They work well. Stans has larger 'grit' in it so might seal bigger holes but is not suitable for squirting into valves for top-up as JRA is.
I read recently about ammonia in some solutions added to stabilise the latex content, and which can rot the tyres. Stan of Stan's says here that it's not a worry for their stuff though: http://www.velonews.com/article/82082. I've not noticed any tyre-rot presonally with JRA either, even over 1 year.
Effetto Caffe Latex uses synthetic latex and no ammonia. It also foams up. So, it sounds good.
JRA is cheapest £15 per litre, Stans slightly more at £18 for 946ml, Caffe Latex £25 per litre.
Anyone tried Caffe Latex?
Caffe Latex: http://www.ukbikestore.co.uk/product/91/e_ltx_s/effetto-caffe-latex-sealant.html