Syn and I use it religiously, if that isn't good enough then it is definitely bad.
You can see what these dex clones are doing all over the net, many people have completely choked off systems at some point that leads to engine failure. Can happen at any point, 20k miles, 40 or 100k plus, or not at all. If you use RMI25, any contaminant in your cooling system ends up in your overflow tank. So you will at least know if there is a problem when you will never know w/o RMI25. Plus, if you drain 10 ounces or so of your coolant a year, and put RM25 back in it's spot, you will likely never have to change your coolant as it also re-pleats your additive package. Coolant never goes bad, the additives do.
Major weakness of dex clones is they have no cleaning ability. Huge deficiency.