Im looking into getting an overdrive to tighten up the low end on my JVM. And to drive the bollocks off my Amp.

So im wondering would a Bad Monkey do the job or is it worth buying something a little more expensive such as a Maxon or possibly even something else if you have any recomendations?

Depends if you want to spend the extra money, the Bad Monkey is good for the money but getting a really good pedal like an OD808 or OD9 will be much better.
Hey man I've got a bad monkey and I love it. It's really good value for money and does the job well.