Ok for large chain rings
The spirit guide worked pretty well when I was using a 32 tooth chain ring. I did eventually drop the chain because it came off the bottom of the chainring and I back peddled it through the guide. It was very hard to get the chain back on, I ended up having to remove the guide most of the way.
I recently went to a 30 tooth chain ring and find I’m dropping my chain about as much as I did with no chain guide at all