The difference between the two should be minimal:
M2 and M5 are effectively the same, and the difference is how the graphics are applied to the bat. Some people will tell you that M2 is sooooooooo much better, but it's the same composite.
I would not pay a penny over MSRP for either, and don't even love the MSRP price for the Ignite. There's really not much difference between most of the Monsta bats produced over the last few years - the composite is the same, and then it comes down to weighting and whether you want a 1pc or 2pc. Plenty of options at $200 or less around the FB groups.
I would also not overlook a DeMarini Flipper/Nihlist/Whatever they're calling it these days or a Worth Krecher or the newer Pure ASA stuff. While Monsta is the popular option, let's not believe it's the ONLY option.