Just my opinion...
-SEP is far from resource hog. Might be the most "lightest" complete security solution for workstations/laptops/servers in market at the moment.
-Have seen plenty of damage done with SEP.
For example, have seen more than few places where some "worked all my life on IT business" had configured SEP without firewall protection, end-customer thinking that "-yea now we have a great FW solution, everything works just fine, just fine!"
-Have seen problems with SEP, earliest versions was crab and everyone knows that. Yea, some damage done in past for reputation, but if there's nothing to fix, it would be just very boring:) Still some problems with SEP, but honestly, show me the competitor which doesn't have problems.
-SEP, quite easy to get started with it, quite easy to configure, but still very flexible. Thousands of computers, tens of networks, https from internet, easy to upgrade and deploy... show me competitor doing same things with only one Management server?
-AV/AS/FW/IPS/Application control/NAC.... All in one client? Yes, with SEP. Might be something to point out when having problems/bugs, is there too much in one client?
I know that this might sound like bullshit and marketing speak, but no it's not. I've been some kind of specialist with Trend Micro's OfficeScan and that antique ServerProtect, have worked with Mcafee and F-secure, so i do know little about what I'm talking.
My main area and focus on IT is securing data, have been for some years. I know something about today's security area, what are difficulties and solutions and so on.
Still, you need to find out what is the best product for your use and only you will make that last decision. Sometimes it's price, sometimes marketing people's words, sometimes what you have read from internet...