"does nobody else think Microsoft Security Essentials does a damn good job "
It certainly behaves itself - light on resources, quick, invisible, doesn't nag, and (as far as I know) it hasn't let me down. But most lab test results for MSE are less good against free alternatives, and even "real world testing" scenarios show it lags dedicated free products by sizeable margins. Do a search on dottech real life detection rates (or read other tests) and see what you conclude. I'd not put too much store by pure lab tests as there's too much gaming by different vested interests, but the various real world scenarios still tend to suggest that MSE isn't technically quite as good as third party products.
From the MS Security Intelligence Report for 1H14, around 2.4% of WIndows 8.1 machines with no active AV protection (ie MSE turned off and no third party AV active and up to date) had reported problems. For machines with any form of active and unexpired AV the WIn8 infection rate was around 0.6%. In reality the 10% difference in performance between best AV and MSE is not very significant - the most common problems of AV infection are down to expired or inactivated AV products, plus user behaviour.
On balance I'm sticking with MSE - I know its not the best, on the other hand I'll take the risk because I've found third party products unduly intrusive and resource heavy, and because I avoid using attack vectors like IE, Acrobat and Java, and to keep reluctantly tolerated rubbish like Flash under control with Flashblock.