The new terminal is clearly impressive and provides a much-needed upgrade for LaGuardia Airport. My favorite aspect, however, isn't just one specific feature but it's that the new facility allows the rest of the airport to shine.
Among others, LaGuardia is a small airport so taxi times are short when there are no delays and the new terminal removes a good chunk of the congestion that plagued on-time departures and arrivals. For example, passengers will no longer have to wait for the plane behind theirs to move before they can pushback and won't have to wait as long to taxi into the gate on arrival.
On top of that, it's the closest airport to Manhattan, and flying out of LaGuardia is typically more convenient than John F. Kennedy International or Newark Liberty International. Its proximity to the city also means passengers are treated to the best views of the city on arrival and departure.
The reason some travelers hated going there is that its infrastructure paled in comparison to other area airports. Now that the airport boasts modern facilities, flyers can enjoy the other understated aspects of LaGuardia.