So the Maxim deals 0.0065 suppression per bullet which is 3.25% the required amount to suppress a unit on grey cover. It has a rate of fire of 7.2 rounds per second at long range which means it will suppress a squad after about 4.3 seconds. The maxim has a long range burst length of 4.5 seconds which means that really under only perfect conditions will the maxim be able to suppress a squad at long range in one burst.
The MG42 deals 0.012 suppression per bullet which is 6% the required amount to suppress a unit on grey cover. It has a rate of fire of 14.4 rounds per second at long range which means it will suppress a squad after roughly 1.15 seconds. Burst duration is only 1.63 at long range compared to the maxim at 4.5, but it doesn't matter since it suppresses a squad in 1/4 the time.
As an extra, the vickers under the same conditions should take roughly 1.725 seconds to suppress at the same range. This is assuming the vickers does not outright kill the model its shooting at though, because if it does(which happens semi frequently) the MG will cease firing and attempt to acquire a new target model which obviously cuts the suppression speed.
Obviously this is all just assuming controlled conditions at max range with the enemy squad in neutral grey cover, but it should demonstrate how much better the MG42 (or even vickers) is compared to the maxim. It's not just a little worse, the maxim is just plain bad in terms of suppression.
From some cursory testing I did in cheatmod, it doesn't seem to work out quite like this in practice, though. I don't know if there's something else going on with the numbers, or if there was something wrong with my methodology of "Put conscript squad at max range of MG and switch MG to 'enemy'"
It generally took just over a second for the MG42 to suppress the squad, but the Maxim only took 2-2.5~ seconds every time i tested it. Suppressed within a single burst every time, with a reasonable amount of the burst to go.
The main thing noticable was that the maxim takes significantly longer to pin, suppression certainly didnt seem to take four and a half seconds, however.
Clarifications: MG was replaced with a fresh MG every test, as was the conscript squad, to avoid issues with lingering suppression, or the MG being mid-burst.
I'd urge others to do a more thorough examination, perhaps I made a mistake somewhere, but it really doesn't feel as though the Maxim takes the amount of time it's "meant to" to suppress.