Sounds like we are in the same boat right now. I attached my budget plan here, and near as I can tell the Quattro 5000 is the way to go for this application. I should write more notes when I am researching, but I know there were some reasons to go Quattro over Multiplus.
I looked at Magnum, even many of the "Geek" friends who have Magnum have all said they would go Victron next time. I guess I have not seen anyone with reliability issuses, but I think there are probably less of them out there than Magnum in an RV application at this point?
If I am understanding correctly, the one thing the monitor is giving you, is wifi, so that you can monitor and control your system from anywhere, vs only being able to do it bluetooth, which you could do without installing the monitor at all. I was considering going without the monitor, just because my "control center" is pretty full, and my phone is always in my pocket. The victron site shows a "Venus" that gives you the wifi stuff, without a monitor, but I can't find it actually for sale anywhere, so I don't know if it is new or what. I emailed the supplier on my document there, but have seen nothing back from them yet on it.
Solar.pdf