Are you in Boston already, or will you need to get into the city first? And, is price an issue?

IF it is easy for you to get to South Station, AND you don't mid the price premium, take Acela. It is more comfortable and delivers you right into Midtown. Problem is that South Station sucks if you have to drive into the city - no cheap, easy parking.

It is such a short flight that there is not much difference with airlines. Personally I like JetBlue - you at least get a drink and package of chips or cookies. They seem decent enough with on-time performance considering it is Laguardia and things always get delayed.

Actually I find I prefer to go to JFK. It is a little further out, but if I am going to midtown, it is cheaper and pretty easy to take the airtrain to Jamaica Station and grab the LIRR in. From LaGuardia you NEED to take a taxi or Uber/Lyft, and that is a huge mess right now.