i recently got a sample of OID and prima hydro to test against 425.
i personally like the 425 the best. then comes OID. i too needed to cut the OID down to roughly 3.5-4:1 because of the streaking that occurred on my metallic black paint. on my white daily driver i could hardly see any streaking of course but im sure if i looked hard enough its there. that and the paint darkening effect slightly turned me off to OID. it darkened my deep metallic blue custom paint job to a point where it looked black in my garage.
OID is extremely cost effective though, especially if u start diluting 4:1 like i needed to.
i live in hawaii so 425 by the gallon isnt as cheap as you continental detailers, but i think i could safely say id have a hard time deciding on what to buy when i run out of QD's because 425 is favored that much more but cost over 40 a gal while OID makes a little more than a gallon if you dilute 4:1 and costs only $20 for a 32oz concentrate. if i could dilute 425, it would be a no brainer.
P.S. am i the only one that doesnt like the OID bubble gum smell?? it reminds me of dental fluoride...