These tests are great for practise but definitely need improvement in verbal

I started using these test sometime back and consider myself qualified enough to review based on my 3 tests. Something to take note of, I have also given the practise tests from Kaplan, Veritas Prep, Manhattan GMAT, The Economist before giving GMAT Club tests. Also, I have my GMAT scheduled on 20th July, so will update on the score accuracy after that.

Interface - I like the simple interface of the GMAT Club test. It is less distracting to eye and the next question loads faster. The font size seems adequate and it aids you to read the text without much of scrolling, which is generally required to be done for RC's

Question Quality - Given the previous tests, I feel the questions in Quant were quite upto mark with the OG questions, though marginally harder than it. Although, Manhattan remains the toughest Quant test of the many I appeared. GMAT Club test question, especially for Quant sometimes are tricky more than laborious, which is exactly what GMAT Quant is all about. I found the Word problems and Probablity questions quite tricky. For the Verbal questions, I found few of the question quite vague with answers ambiguous. In terms of quality of questions, I didn't find it at par with other GMAT tests. Although, some of the questions in GC were really good but overall it helps if there are no questions that are unclear because it unnecessarily wastes your precious minutes between the exam. I will reserve my comment on the score, until my GMAT.

Analytics - I love the analytics. I find it quite satisfying with those graphs and added stats for questions. I liked it more because unlike other tests, which give you the reasoning behind correct answers, GMAT club gives you link of the forum discussion. It helps tremenduously because many times you are not satisfied with the explanations and you can seek clarity on the forum then and there itself regarding the explanation unlike other tests.

I would surely recommend them to someone who wants to practise CAT's because I think that it will improve as it progresses.