When they work, they work great. When they fail, you have to be completely on top of a stand alone system and understand exactly how it's wired and what to do when things don't work. If you're OK with that, they're fine.
For E-85, they are a pretty good application. We also have Selin/SZ Tune switch/ BC cars running E-85. Can't get those components anymore, so stand-alone is the way to go for ethanol.