It depends what headphone you are going to pair it with. The one headphone I have extensive knowledge with the Magni (as it's part of my office rig) is the Mad Dog and that pairing is amazing. An HD700 or HD800, no because they don't fare so well with regular bright solid state amps, as both are fairly bright headphones. I haven't even considered running the HD800 off a Magni. People have said great things about Vali paired with bright headphones though, so that is probably a more apt comparison. I would welcome the chance to try the Vali/HD800 pairing.
If cash if a concern, also remember the first thing I did with the Lyr was upgrade the stock tubes. So factor in extra for that as well.
For the Lyr, you are mostly paying to take the edge of the highs (Magni can be edgy up there) and more overall headroom vs the Magni, plus the option to taylor the sound to your liking with tube rolling. Not 6x better, but definitely 2x or 3x better once you upgrade the tubes. 'Tis the law of diminishing returns.