Criticism and Acceptance of the Shulhan Arukh

On Thursday, while waiting at the doctor's office, I came across the following quotation from Asher Siev's 1943 PhD dissertation "The Period, Life and Work of Rabbi Moses Isserles" (Yeshiva University) on page 73 concerning criticism of the Shulhan Arukh:

R. Moses Yafeh, a pupil of R. Isserles, felt that the Shulchan Aruch, both of R. Caro and R. Isserles, is inadequate because it fails to give the sources of each law. This caused him to compose his Levushim in which he elaborates, gives the origin and reason of the law, and often disregards Rabbis Caro and Isserles together. R. Meir of Lublin (MaHaram of Lublin) opposed the Shulchan Aruch and also the Levushim on the ground that many stumble and misinterpret the law as a result of consulting such abbreviated works.
There were others who objected to the Shulchan Aruch. These objections resulted from a belief that the simplification and codification of the Law will do more harm than good, for it will discourage intensive study and also will serve as a tool in the hands of ignorant people who, with the aid of such a digest, will pose as Rabbis and scholars.

However, Siev continues on pp. 73-74 concerning the acceptance of said work:

Nevertheless, the Shulchan Aruch was accepted by the greatest majority of the Rabbis of the day. The Sefaradim accepted the authority of the Bet Yoseph, while the Ashkenazim reserved the right to follow R. Isserles whenever the two disagreed. The pupils of R. Isserles helped in spreading his works as well as influence amonth the Rabbis of all lands. The more prominent of these are R. Joshua Falk (סמ"ע) and R. Benjamin Ashkenazi (בעל שו"ת משאת בנימין). The former, being the first to place a commentary on the Shulchan Aruch, endeavored to side with its authors and to explain every difficulty and objection that was raised against them. He took special pains to justify R. Isserles and was even accused of inserting in the writings of his teacher interpretations of which the latter never dreamt. R. Salnik wrote: “In all the lands of the Ashkenazim, the opinions of R. Isserles were accepted and we follow him in everything.” Also, “since this decision came from my teacher, R. Moses Isserles of blessed memory, far be it from me to be lenient and lift my head against him.”
After these eminent authorities, there followed a host of others who strengthened the influence and authority of the Shulchan Aruch. Of them, we may mention R. Isaiah Segal Hurwitz (השלה), who testified that, already in his day, the decisions of R. Isserles spread in all lands, R. Joel Sirkish (ב"ח), R. YomTov Heller (תוס' יו"ט), R. Jacob Joshua b. R. Zvi (בעל שו"ת פני יהושע), R. Samuel Zeinvil, R. Menachem Mendil of Nikelshpurg (צמח צדק) and his son-in-law, R. Gershon Ashkenazi (עבודת הגרשוני) etc.
The authority of the Shulchan Aruch was even more strengthened after the two valuable emendations of R. David Segal (ט"ז) and R. Shabtai Katz (ש"ך). These eminent scholars added invaluable lucidity to the texts and put the seal of final approval to the great work of the Bet Yoseph and R. Isserles.