I'm running an Innovate setup in my Duster. It really should be used as an aid and AFR verified with a plug reading every now and then. Don't get too caught up in the numbers themselves, give the engine what it wants. It was a godsend for me though I learned a lot about tuning once I started using one; since leearning the relationship between AFR and how an engine "feels" I can comfortably tune other vehicles (like my D200) without needing a wideband and AFR gauge. It's also really nice to be able to see instant real-time changes in AFR with changes in ambient conditions and can also be a way to tell if the engine is experiencing an issue. Sudden over-rich readings indicate dead cylinder or misfire, lean readings indicate fuel delivery issues or vacuum leaks etc.
Something I haven't yet done but would like to is data logging so you can see the AFR changes over time. It can be kind of hard (and unsafe) to constantly watch the gauge while doing a WOT run lol.