Roslynmuse, from the very first hearing, it has always blown me away.  Ernani suggests: 'Why not try Karajan's BPO recording?' and I agree.  It isn't underplayed (!) but I find it incredibly powerful and moving.
The piece is such a personal and emotional statement - it always leaves me in an emotional puddle.  I can't imagine anybody being unaffected by it.  Perhaps the key point is that I've never tried to analyse it - any attempt to do so simply detaches me from the experience and the music drags me back. 
Just get a glass of wine, close your eyes, and experience the music.....

I first encountered metamorphosen on a string quartet course in Oxford as a teenager.  A bunch of the quartets got together to have a play through.

I immediately took to the work, perhaps because of being right in amidst the lush string sounds. 

But it was a lot later that I listened to a performance, and I have to say it took a while to get into listening to the piece rather than playing it.  I think performances need to walk a tightrope with this work - get as much intensity in each players lines without losing the sense that some threads should come out more than others.  When thinking about the individual lines this work is a lot more 'classical' than you might initially think.

Tommo

The experience from inside the music is very different, isn't it?

I was a (very poor) cellist at school, when I scrubbed my way through Brahms' second symphony - a work in which I hear the cello line above all others to this day (30-odd years later).

Later, I became a (slightly better) percussionist, which allowed plenty of time for listening to the orchestra from an unusual vantage point. I haven't played for 20 years, but to this day I prefer to sit behind the orchestra at concerts 

As for Verklarte Nacht, I vote for Karajan - excess is everything in such a fin de siecle work!

And in Metamorphosen, I too like Karajan and the BPO strings... but the performance in which it first really made sense to me is the cool, but eminently rational 1953 recording by Clemens Krauss and the Bamberg SO - probably not available any more...

The CD I have of VN also has op5 Pelleas and Melisande (karajan) - i have tried to get into this piece and like bits and pieces of it but find it rather difficult - not as romantic as VN but not yet in the more radical stage - wonder if anyone else has views on this work