Boxing is awesome!
I am not of the most knowledgable ones here, but I have been boxing for a while now, about 6 months on my own and 4-5 weeks with a trainer. I found there are a lot of benefits to it, and up to an extent my muscle tone has become better from boxing complimentary to my weight training. It's very high intensity, but it's very important you get the technique first, right way to punch, move the hips, feet..etc before going all crazy on the bag
It's really a great cardio/strength workout if you incoporate with rounds an exercises
Round one: certain boxing technique (i.e.) uppercut, uppercut, straight straight for 3 mins, then on the floor for planks (elbow elbow, palm plam) plank 1 min
Round two: hook, straight, hook for 3 mins, then 20 pushups...
this is just an mini example of what I do, you wanna make sure you warm up the muscles before and do a bit of light jogging ahead of time.
hope that helps!