I have been riding Amtrak 4 to 6 times a year for several years. Most often I travel between New York Penn Station and Providence but occasionally I travel between Newark, NJ and Washington, DC. In over 20 years of riding I have had one seriously late train (over an hour). I have ridden Amtrak during snow storms when everything else was shut down. I have also used Amtrak for long trips, Newark, NJ to New Orleans and also around the country. For my regular jaunts between NYP and Providence I use Northeast Regional Service; it is important to buy your ticket in advance as the price increases as departure nears. Cars are clean with large comfortable seats. Reading lights and tray tables work as they should. Personnel are helpful although beyond collecting my ticket I have few interactions with train personnel. My one suggestion is that food be purchased in the station where there are excellent take out places and carried into the train. My Providence trip takes just under 4 hours; flying would not be faster and with TSA waiting probably longer. I am not commenting on Acela as I have never used it. But Amtrak is a wonderful resource and more people should take advantage of it.
Note: Because of coronavirus I have not traveled since early this year.