The new claw-hand does not actually come with positive mental associations. He doesn't remember the actual decision to get it, but he remembers his mindframe afterwards— which is essentially that he was VERY VERY ANGRY and was throwing away his humanity and fighting and revenge and he wasn't exactly entirely sane at the time. . . In general, he was Not In A Good Mental Place… it was a very different sort of head space than the one he's currently residing in. So it's a bit of an uncomfortable reminder of a lot of things he's trying not to think about in regards to the last parts of his life before Aather (the parts he's aware of, at least).

That being said, Torrent and Echo's responses to it being overwhelmingly positive and impressed has actually moved him a little bit away from having completely negative views on it. His initial reaction to it was the idea of hiding it and ignoring it completely, but the two of them have brought him a little closer to the idea of being comfortable with actually using it as something OTHER than a reminder of everything going horribly wrong. It's not likely to be his weapon of choice basically ever, but he's a lot more of accepting of it in this more comfortable setting.

I'm actually curious on Tsunami's thoughts on the Echo/Zwei situation.