The Pass Aleph series amps are very detailed and direct, but the affordable models are only 30 or 50 wpc. They do have bigger Aleph models and they have the newer X-series, but they start getting more expensive. I would definitely recommmend listening to some amps in your home before buying. I'm not sure if you would like the sound of the Pass with Megadeath or Metallica. I'm not putting down the music at all...it's just that the amps are very detailed and neutral, and you may not prefer the way their lower powered amps portray distorted rock, and they may not be able to go as loud as you might prefer. I owned an Aleph 3 and, though I appreciated a lot about it's design, purity, and musical detail, I never found myself tapping along as I listened. I constantly found myself distracted and I wasn't enjoying the music. It's an amazing amp, but it wasn't the right amp for me...with my system.
All amps are designed by people with individual tastes and they will appeal people's individual tastes. Some are better at portraying certain styles of music than others...probably due to the designer's individual tastes. Besides all that, you need to know how the amp will mate with your preamp, speakers, and the rest of your system. There are many amazing preamps, amps, and speakers, but they won't sound amazing if they're not matched with compatible components...that's why it's so important to try the amp in your room, with your system and your music.
All amps are designed by people with individual tastes and they will appeal people's individual tastes. Some are better at portraying certain styles of music than others...probably due to the designer's individual tastes. Besides all that, you need to know how the amp will mate with your preamp, speakers, and the rest of your system. There are many amazing preamps, amps, and speakers, but they won't sound amazing if they're not matched with compatible components...that's why it's so important to try the amp in your room, with your system and your music.