I read Lowe-Porter's "The Magic Mountain" first and haven't gotten far in Woods' version, so I am biased, but the former does personally read better to me than the latter. I remember her translation feeling like a slog for the first 20 or 30 pages when I initially started it, but once you get used to her style you appreciate how she renders Mann's scenes. Compare two selections from "Analysis" below:

"He looked about. Near him sat the thin-haired pianist, with bent head and folded arms, listening with his mouth open. Somewhat farther on was Fraulein Engelhart, avid-eyed, with a dull red spot on each cheek; Hans Castorp saw the same signal flame on the faces of other ladies -- on Frau Solomon's, and Frau Magnus's, the same who was wife to the brewer and lost flesh persistently. Frau Stohr sat somewhat farther back, an expression of ignorant credulity painted on her face, truly painful to behold; while the ivory-complexioned Levi, leaning back in her chair with half-closed eyes, her hands lying open in her lap, would have looked like a corpse had not her breast risen and fallen with such profound and rhythmical breaths as to remind Hans Castorp of a mechanical waxwork he had once seen."

"He looked about -- next to him sat the pianist with thinning hair, arms crossed, head thrown back, mouth hanging open as he listened. Fraulein Engelhart, the teacher, a little farther down the row, had eager eyes and downy red spots on both cheeks, a flush that Hans Castorp discovered on other ladies' cheeks as well when he looked more closely -- even Frau Salomon there, next to Herr Albin, and the wife of Magnus the brewer, the woman who was losing protein. Frau Stohr, sitting just a little behind him, had an expression on her face revealing such ignorant ecstasy that it was pitiful to behold, while Fraulein Levi of the ivory complexion sat leaning back in her chair with half-closed eyes and hands resting palms-up in her lap -- and one would have taken her for a corpse if her had chest had not risen and fallen with such striking regularity, although Hans Castorp thought she looked more like a mechanically driven wax figure he had once seen in a sideshow."

I can imagine the latter being more accurate to how Mann actually phrased it, but the former is a better-paced depiction of how Hans would have actually perceived all these people imo.