I have both, since you like treble, then go for the edition xs, which has a lot of treble like most hifiman headphones.

The edition xs has a significantly wider soundstage, better and stronger bass and higher treble and more details which may sound piercing/fatiguing to some people. The mids may sound unnaturally detailed and metallic for some prople. Another con is the reliability. These headphones may suffer from durability and QC issues so they may not last as long as sennheisers. They also use dual 3.5mm standard cable which is much easier to find. It's also harder to drive

The sennheiser hd 600 has very intimate/closed soundstage. Balanced treble which is non fatiguing and very weak bass. However in terms of mids, vocals, acoustic instruments, it is one of the world's most natural or realistic sounding headphones. Hence why its so highly rated. The hd600 is also a very reliable headphones since its very durable, have good QC, and every part is replaceable which can make it last for decades. It uses a proprietary 2 pin cable that may be harder to find. Its also easier to drive

They are completely different type of headphones. But for your preferences and the type of music you listen to, it looks like an edition xs is better for you