I've been listening to Wagner for about 20 years, to Mahler for about 10. I occasionally pull out a score, but I'm a musical amateur and lack the analytical chops of many on this board.
Both composers "get to me." And for similar reasons: the ideas are huge, the insights profound, the details are super-fine, and the music is always beautiful. If I were to go to a dessert island, both composers would have to go with me.
But let's face it, they're both long-winded. Wagner's operas are double-long, and so are Mahler's symphonies. I'm willing to put in the time because ultimately it's worth it.
I'm afraid I'm about to speak a heresy here, so apoligies in advance, but here goes: although Wagner is terribly long-winded, Mahler has a flaw that I don't see in Wagner, since Wagner continually develops his themes, moving forward, however slowly. But Mahler has the flaw of REPETITIVENESS which I find less forgivable. For instance in the first movmement of the Third (M3), I feel like I go on a long journey with Mahler and then when we've come through the mud into a better place, we're just back in the mud. I haven't looked at the score, but I'd swear there are repeat signs in there. What's up with that? Necessary?
I'm interested to hear people's thoughts, since I've learned a lot here, and what I've learned has really enriched my appreciation of Mahler.
db
One of the most pitiful stories I've ever heard about an individual's introduction to Wagner came from my wife. She had a professional mentor years ago in the early part of her career who was also an opera nut. While she was working in downtown Chicago, her mentor took her to a Chicago Lyric Opera production of Siegfried - that's about as extreme as it gets to introduce a novice to Wagner!
One thing that has helped me maintain an interest in Wagner is that I took German many years ago, and have tried to maintain some familiarity with it by listening to Wagnerian opera, without having to travel to Germany. Some familiarity with the language will help in getting through the lengthy portions of the operas. Also, study the synopses describing the action (or lack thereof) that accompany libretti of the operas. The more you read, study, and listen, the easier it eventually becomes to digest what's going on. Opera nuts have been doing this for years, they know the operas by heart, and they know who sounds good at this particular spot in the opera, etc., etc.
I might suggest one section of a Wagner opera that may sustain your interest for about the last third of its first act: That of the Transformation Music and Grail Hall Scene from "Parsifal". This is quite magisterial music that Wagner skillfully develops into what is to my ears, essentially a 45-minute tone poem. The orchestra plays a significant part in this section, though the voices of the Grail knights and the voices on high add considerable effect as well. Though solemn, you will not find much grander and sublime music elsewhere. The last scene of the third act is even more solemn and gloomier, but the closing minutes of the opera are absolutely sublime.
Note that many epic movie soundtracks, such as that of "Ben-Hur" (composed by Miklos Rosza) rely on the heavy use of leitmotiv (or signature themes) in their works, the same tool which Wagner introduced and employed in his operas. This is one instance of how Wagner not only influenced subsequent composers' music, but how he also influenced Hollywood - many of Hollywood's lengthy epic movies are around four hours - the same length of the majority of Wagner's operas.
While on the subject of leitmotiv - there is an excellent album that appeared shortly after the Solti Ring was released, titled "An Introduction to Wagner's Ring". This was a three-record set that featured commentary by both Wagner and Mahler scholar Deryck Cooke, along with musical examples from the Solti recordings illustrating the leitmotives. I think this was later released on CD, but might be hard to find.
Wade