Seconded. I make my own now - because quality nitro is not available locally (and i don't consider traxxas fuels to be quality - i never noticed more varnish in my engines than after running a while with traxxas blue fuel)
Keep in mind - some states have HEFTY hazmat fees for shipping nitro. In my case, i get hit with a state and city fee, so it isn't economical to make my own nitro until i'm ordering nitro in a full case of 4 gallons or more (same fee regardless of amount)
understanding that 4 gallons of nitro will make an IMMENSE amount of fuel - its good to partner up with a ocal RC group or friends, to split the cost and the fuel ( the amount of fuel would go bad since it absorbs water over time... and would take years for me to go through on my own unless i got into big rc planes or something)
I use castor and syntehtic - Klotz techniplate as the majority of the oil mix, and a smaller percentage than listed above, as a safety measure. Organic oils have a higher burn temp... that's right - a syntehtic oil will burn sooner (hence cleaner) in the combustion process.. which is a good thing and a bad thing. Good if everything is running perfectly.. it'll be a cleaner burn. Less varnish, less mess, etc. Bad because - lets face it... we all tend to push our machines.. castor oil is better when you're running too hot, or lean, etc... it'll cling around for that last bit of dieseling to coat things before being burned up.
If you can get high concentrate nitro locally (try drag strips) then making your own is a MUST. you get to control the quality of the product, and save money too. If you have to ship it, and get hit with hazmat - it can still work out per gallon... but you have to order enough to justify it, and almost certainly split the quantity with someone.