Young Justice got cancelled in part because of merchandise (the symbionic titan effect) and in part because action cartoons have always had a hard time finding their niche, outside of specialized blocks. Honestly, I was impressed young justice stuck around as long as it did. Two seasons seemed the max for any action series that doesn't feature Ben 10.
Teen Titans GO! is a random comedy, which, if the success of Adventure Time and Uncle Grandpa didn't make clear, is all the rage these days. Plus, as was mentioned above it's insanely cheap to produce. The most limited of limited animation. Hell, in all the episodes of the show I've seen, I can count on one hand the number of times Raven has walked as opposed to floating, or used her hands instead of her powers.
As to my feelings on the subject... Eh... I was never big into young justice. As a marvel man, DC heroes just don't do it for me, besides, like I said, comparatively speaking Young Justice got an okay run. Compared to how Thundercats 2011, Generator Rex, and Sym Bionic titan got the shaft.
Teen titans GO! has quite a few legitimately funny episodes, and all sorts of nerdy references from all kinds of fandoms, which is always fun (one episode even had a shoutout to fallout 3.) Unfortunately, the series also does the "Family guy" thing, where it makes the entire cast a gaggle of selfish, unlikable assholes, which can ruin the comedy if it crosses into "I no longer care what happens to these terrible stains of humanity" territory. Robin and Beast Boy get the worst of this, though it happens to all from time to time.
tl;dr... I'm neutral on both shows, so I guess I can just go with the flow. XD