Does anyone have any experience with using the "new" refrigerants on flooded systems?

In Australasia (and probably elsewhere too) back in the late 80s and early 90s R22 was promoted as the way forward as a replacement for R502 for low temp systems in new systems for clients that weren't keen to go ammonia. Advertising with such memorable phrases as: "R22 - the green alternative" and "R22 - Part of the solution, not part of the problem" were common. Consequently a significant number of major low temp installations were done with R22 and guess what? We are back where we started when R502 was on its way out except now the issue is with R22. Personally I won't be sad to see the back of LT R22 and all the hassles that came with it - high discharge temperatures, oil recovery from flooded separators etc. Trouble is a lot of these systems were big (for non NH3 systems) up to 5000kg of refrigerant and while I'd be happy to sell them ammonia, 30 or so replacment coils and re-run all the copper in steel there are other issues; Ammonia that gets contaminated by HCFC creates some seriously corrosive and dangerous compounds, production plant down time is not an option and the cost would be enormous.

And so to my question - has anyone used R404a, R407c or R507 on flooded applications?? An aozetrope fluid like R507 would be my pick but I have not found anyone thats done it before.

Any comments appreciated.