I'm not overly a video person, but rather more of an audio person when it comes to opera. I prefer to sit back, close my eyes, and simply enjoy the music. Indeed they majority of what's on the MET site is audio, but there are increasing numbers of videos as well.
I would definitely suggest taking the free trial which is what I did initially. I then subscribed a couple of years later for a month to catch up on new performances that were added. I have not done so in the last few years because frankly many of the Bel Canto operas which are my main focus have not received outstanding performances by the currrnt crop of singers. Plus, I record the Saturday afternoon broadcasts that interest me and consequently have most of what I want.
The free trial is the perfect way to "broaden your horizons". Do listen to singers of the recent past and compare them to many of today's singers. Train your ears to listen carefully. While we have many wonderful singers today some would be considered also rans in times past. Conversely some of today's singers totally outclass some of the older generation. Listen and learn! Others and I have contributed much regarding singers of the past and present in the opera section of this forum. As and example there is the recent thread on Rossini's Semiramide. (There is even a recent thread about Muscle at the MET! That's where the video part is worth its weight in gold!)
Bottom line: ENJOY the wonderful world that you are about to explore!
Edit: PS: For libretti I do a google search and find the one with the best up to date translation. Some sites give the libretto only in the original language or offer stilted Victorian versions that don't quite fly today.
