I used this mod since a couple years now.
In my eyes, these are the highlights:
-Tons of replayability added
-Missing/ planned content added back in the game, games feel more complete and polished
-More coherent mission listing and single-player experience
-Multiplayer fully working on this mod, flawlessly in most cases.
-Game get slightly harder , more challenging. (penalties , AI overhaul , more impredictability)
-The mod keep it real with the base game, nothing feels out of place
-The 2 extra maps are a welcome addition.
-Huge number of quality of life improvements
The mod description is accurate. I think the SEF experience is actually the best way to play Swat 4 nowadays.
This mod have almost no downside. For what it adds to the base game, I say take it 100 % of the time, especially if you have already finished the game.
I give this mod a overall rating of 95/100.