Hello @David_Baldonado,
I can only second @chris The support is great. Of cause there is a difference in reaction time between enterprise and free tier - but that should be obvious. The enterprise support worked super good every time I needed it. You are asked to add a severity to your case. Sometimes I even with an low S4 I got a response in hours with is much faster than the SLA.
As a consultant in the area of noSQL DBs I deal also with other DBs than MongoDB - I can easily state that the MongoDB support is the best around.
Disclaimer: This is all personal experience and I speak on my own.
Regrads,
Michael