Speaking from the center, and as a former leftie, I say they're essentially equal - except intensified on the left. True, McCain and Palin ran a pretty nasty campaign, but your "side" has long since more than made up for it.
I never saw Republicans threaten to abandon their country outright and move to Canada if Obama was elected (and then lie that they were ever going to do it; I personally know two people who did this).
I never saw Republicans enact a decapitation of Obama on tv.
I never saw Republicans go out in mobs stopping traffic, looting stores, and setting cars on fire just because their participation-trophied pansy pussy asses lost.
I never saw Republicans threaten to take a treasured constitutional liberty from the bill of rights and then slander the other side as evil when the other side rightly called bullsh*t on the comically false pretexts of the constitional violation.
I never saw Republicans manufacture the most stretched, bullsh*t excuses for impeachment just because they didn't win.
And don't get me started on issues of substance like the Clinton foundation, this is just the polarization stuff.
Ymmv, it always does, - but this is how it looks from the center (former consistent voter for Democrats), and why you maybe shouldn't bet too heavy on whatever quasi-socialist joker the Dems finally nominate. Just sayin'.