Depends on who you ask.
There's always a bit of subjectivity on whether or not a dub is faithful enough. There are those out there who believe a dub isn't faithful unless the script is completely identical to the subtitles (which never happens because it isn't practical), and there are those out there who believe as long as the "spirit" is intact in a very general sense, then it's a faithful dub. Like, to give you an idea, the original producer of the English dub of DBZ, Barry Watson, said that he believed what they did with DBZ was faithful to the Japanese version.
..........Which, I mean......doing my damndest to see things from his point of view, it's not as though they pulled a Robotech and used pre-existing animation to tell an original story, so, from that point of view, I guess you could consider it faithful..........buuuuut, I and many others don't believe it was faithful enough. Like, not nearly faithful enough. Like, "Guys, c'mon"-levels of not faithful enough.
So the answer to that question is going to vary on a case-by-case, person-by-person basis. Personally, yes, the Kai dub was faithful enough for me. I would have adapted a few lines differently, and I would have kept the attack names consistent, but overall I thought it was a great dub of the English version, reaching the zenith of its quality during the Freeza arc. Great acting, great casting, great writing, just great to listen to from start to finish.
Still, there are others for whom the Kai dub was not enough, including some who believe the idea of the Kai dub being "better" is a myth entirely. So, to each their own.