MRTG replacement for our agency

Hello All

I have been forced volunteered to find a replacement for MRTG. I have been going through multiple recommendations and researching it and now I find I am in analysis paralysis. Some of the limits I have been constrained to are:
1. Windows based (there goes nagios/cacti). My agency is bucking the trend and moving from open source to Microsoft.
2. No cloud based NMS. The upper level management doesn't believe it is secure enough.
3. Should be free or low cost.

1. Should be relatively easy to implement and configure.
   

Of course as soon as I find options they are shot down. Currently I am looking at the following:
1. Solarwinds: expensive, and a tad overkill since I am dealing with less than 1000 core network devices

1. PRTG
   
2. ManageEngine OpManager
   
3. Observium
   
4. Whatsup Gold
   
5. Entuity Network Analytics
   

Honorable mentions:

LibreNMS - Opensource so had to ditch

Zabbix - See above

LogicMonitor - Cloud Based so it's a no go.

I was hoping to pick the collective hind mind and see people's thoughts about their options and experiences about any of the above or what solution they went with. Thank you in advance for reading this.