The tour is free, and thus it is a good value (if it were not free, it would not be a good value as it stands). It is a self-guided tour, and this accounts for half of the vast disparity in ratings you will see in other reviews. It consists of a long series of displays, which are equal parts text and samples with occasional multimedia or interactive video screens, and it details the entire process a new coin takes from idea to circulation; about halfway through, there are also windows viewing the actual working "factory" floor. My wife and I were interested in the topic and took time to read every bit of the displays, and we found that we enjoyed the tour a lot and both learned things (despite already both being quite knowledgeable on the topic). We observed many other visitors, and they seemed to be equally divided into (a) families where at least one adult was taking the time to read each display to the group and discuss, and (b) families where they were largely ignoring the displays and just rushing from window to window to look in at the factory. It was very apparent that the "type a" families were having a great time, while "type b" families were cranky and unsatisfied. Use this to decide if *you* should visit... if your family likes to patiently read all the text in museum displays, this tour will be rewarding; if your family prefers action and human interaction and is impatient with or uninterested in lots of reading, you might want to skip this tour.
The other factor that appears to account for the vast difference in ratings between other reviews is whether the factory is in operation at the time of the visit. We visited at midday on a Thursday, and every area of the factory was busy at work. The tour windows are high above the factory with thick glass, so there is no direct interaction with the factory or workers; however, several times, we saw workers glance up to see if any children were passing by on the tour, and if so, they would stop for a moment to wave, and then to hold up the coin or medallion they are working on (this was very kind of them). I can see, however, where the tour might be significantly less interesting with views of a silent and deserted "factory", so I recommend making sure to go on a weekday and not on a holiday.
Those that visit should also be forewarned that (a) you cannot take any photos whatsoever in the mint, and (b) to enter the mint you must pass through the most sensitive and finnicky security screening metal detector I have ever encountered (and I have encountered many, at airports, federal and state buildings, major landmarks, historical sites, etc.)... I had to go so far as to remove the belt from my pants entirely because the very small buckle (smaller than average size, and just the simple kind that is attached to a very cheap belt) was still setting it off, and there is no comfortable or private place after the screening to "put yourself together again" (I had my belt, camera, phone, glasses, wallet, etc. in my arms whilst trying to hold my pants up, all while people were coming rapidly through the checkpoint behind me, and no place to stop and restore my accountrements and my dignity). The screeners were very friendly and helpful, though, as much as possible; be prepared, and this shouldn't spoil a visit.
In all, go if you are interested in how the U.S. makes coins, willing to take your time and read lots of displays, and able to go on a weekday during business hours. If you are missing one of these three components, you might do well to skip it.