from the wing chun perspective, mine at least. xing yi seems like wing chuns internal uncle. also from my experience, its closer to wing chun than taiji.
i think 'faster' misses it, its not faster than taiji but it is more direct, uses the centreline and triangulation more, is more violent and combat orientated.
my other understanding of xing yi is that you have to perform techniques hundreds of times or more, i hear that it can be boring... you dont do a series in a form, you just do a particular move hundreds of times a day until the power develops... I'd recommend cartmell and millars xing yi nei gong.
Ecce nunc patiemur philosphantem nobis asinum?
what transcends the buddha and the law? Cakes.
"Practice is better than Art, because your practice will suffice without art, while the art means nothing without practice." - Hanko Doebringer, 14th century