I have a 1260 Pikes Peak with Marchesini's as well as a Monster 1200R also with Marchesini's.I don’t necessarily dislike this bike enough to get rid of it. I like everything about it, buuuut, the handling could be better. I think I’m going all in though, get the wheels and enjoy.
The 1260 handles just as nice as the lighter Monster.
Moreover, I've ridden MTS demos and my buddy's MTS1200S back to back many many times over.
The 1260 with forged wheels handles noticeably better than the 1200 with cast.
Buy the light wheels and don't look back.