An interesting album, mainly because there's a lot of interesting instrumentation here. Green Day dives into using acoustic guitars more, and the two singles from the album were driven using it. In terms of mixing, it's interesting enough to keep the listener hooked.
This was the best Green Day was ever going to get, because they calmed down the punk style just enough, and gave each song some a little emotion rather than the usual f##k you feeling. This may perhaps be the reason they fell back down to a much lower status and can't escape their trademark, recycled punk style.