What's The Difference Between Microsoft Windows Defender And Microsoft Security Essentials?

I have Defender built into my pc which is Windows 7 but Defender won't work if any other security programs are installed.
After messing about I finally found how to get Defender working properly.
It is good in my opinion considering I am using recommended Zemana as portable.
But...
I am confused.
MSE on quick scan took one hour.
Defender on same system took six minutes on quick scan.

To help me make up my mind I am willing to take one over the other if one lacks a firewall.

Which should I keep?
MSE or Defender?

 

Windows Defender is an antispyware program that shipped with Windows Vista & 7, and can be downloaded for XP.
If you install an antivirus program that includes antispyware, Defender will be disabled.
In Windows 8.x & 10 it's an antivirus program.

Microsoft Security Essentials is an antivirus program for Windows XP, Vista & 7.
In Windows 8.x & 10 it's replaced by Windows Defender.

Windows Firewall is a separate program that's not included with either.

Detailed info over here.
https://en.wikipedia.org/wiki/Windows_Defender
https://en.wikipedia.org/wiki/Microsoft_Security_Essentials

 

I am better off with MSE which provides a better range of protection against threats than Defender which is good in itself.
Did a quick research influenced by your responses.

Windows Firewall is installed on my system and active.