Unlike DGCR, Udisc focuses on finding courses, providing layouts, hole lengths and recording scores. Reviews are an afterthought. The reviews themselves are not rated, there are no trusted reviewers, no option to sort reviews by date or reviewer experience level.
Perhaps it's regional, but most of the folks I play with never heard of DGCR, but everyone uses Udisc. My home course has been in existence for 7 years. During that that it has been reviewed 11 times on DGCR and over 1,500 times on Udisc. Since Udisc asks for nothing more than a simple number rating, lots of folks are happy to comply.
So, in the absence of formal review criteria, how do most players assign that number rating to a course on Udisc? Most, I believe, are rating the course based on the experience they had while playing and not the subtleties of course design. Did they have a great time while playing that day? If yes, then they will more than likely give it a perfect 5.0 in Udisc.