Functionally, it works pretty well. I’ve not had it crash or fail. Generally, it gives me the word with the highest score available. However, it does struggle if I have more than one wildcard tile. If I put 5 letters and 2 “?”, it almost never comes up with the highest point word. This is also true with the screenshot feature.
Also, I do use the free version, so I expect ads, however, some of these ads are too long. I see some reviewers complaining that you can’t exit the ads. You can, but you must wait until the end, and some are more than 30 seconds long. Sometimes, it shows me an ad to import the picture, and then another ad to unlock the best word. That’s fine, but if both ads are long, it means the ratio of time spent using the app to the amount of time watching ads is lopsided. It would be like watching a TV show that had 8 minutes of show and 22 minutes of commercials. The ads are long enough that I just look away and then come back to the app. If they were 10 or 15 seconds long, I would probably watch them.