Lots of ways to train, lots of styles to choose from. They pretty much all work - seriously, look at how many talented and successful Martial Artists there are, how many different competitors/fighters. What I, you, he, she, they, them and that guy do is all different. And that's a good thing.
As for mirror work, for the most part it's the start of the shadow boxing you teach beginners. In Martial Arts, it's the same thing as boxing, just with more techniques because we have more techniques. All the boxers I've trained with had different workouts, different things that worked for them, slightly different ways they used the bag, different ways they shadowboxed. And some were champions. Same for the Martial Arts guys.
Watch this video, really, it's worth it. Shadowboxing at it's finest, only take you five minutes. The guy seems to know what he's doing. If you mentally replace him with yourself, you'll just be using more strikes, because we use what we have and we have more strikes than boxers. And mirror work/shadowboxing is as much about attitude as it is about anything else.
Fast, for sure, but the word "smooth" comes to mind.
