I am also a fan of Premium Comfort, as for me it represents the sweet spot between:
- having space vs paying a lot of money.
- earnings in Delta SkyMiles (including MQD's)

In Premium Comfort I can have a comfortable flight even where the flight is full and someone is sitting next to me. In Economy Comfort if someone is sitting next to me I will not have a comfortable flight (though of course will be bearable in the vast majority of cases). On the routes I am flying Premium Comfort is mostly €150 or so more than standard economy (though I am flexible on dates to get the best prices).