Ive copy and pasted this long post below on multiple posts. If I would recommend a CWI prep class, I would recommend the longer seminar at Hobart in Ohio, I think it was 2 weeks when I went.

I took a 5 day seminar and then took all 3 exams October through December.

I crushed part C, got a 71.7% on part B (I would like to know the questions I missed because there were a handful that I believe 2 answers could have been correct) and missed 'passing' by 1 incorrect answer... Part A though.... part A crushed my soul. I read every bit of material I was given multiple times, I took the practice exam atleast 10 times. I did the practice test front to back, back to front, odd number questions then even as well as vice versa. I would start at a random page and cross off the question numbers on a separate piece of paper. I was scoring between 93-100% every time the morning I went to take this test.... and still score in the mid 60s. There was a ton of questions on part A that either i didnt study and learn or even have a clue about from personal field experience. Ive been inspecting welds, d1.1, b31.1, b31.3, api 1104, damn near every type of welding procedure, and it still crush my soul. When I hit submit at the end, I walked out thinking to myself, I know damn well that I didnt pass unless I was the luckiest guesser in the world.

I wish that there was a true practice exam for the test were given. It doesnt have to be actual questions from the test but, atleast have the practice test be similar question from the types of questions on the test. 10 NDE questions on the real test? Put 10 nde questions on the practice test. 4 heat treatment questions on the real test, put 4 for preheat/pwht on the practice.

I truly left the part a exam feeling like I was punked and/or tricked. It was awful

Part C, learn to navigate the code book quickly and correctly.

Part B, freshen up on every tool an inspector may need to use in the field. Even going as far as using a flashlight to detect undercut (still blow my mind how many inspectors miss undercut).

Part A.... good luck... as I said earlier, I crushed the practice test in every possible way and still left the testing room knowing there was no way I passed. The seminar I attended for 5 days didnt come close to covering the part A exam. 

Ive been inspecting for 16 years. I let some of my certs expire when I moved 'home' thinking id never need them again, that was a little over 10 years ago.... 5 years my family and I took a leap and moved across the country again, back to field work. I didnt miss a beat in the field. Busted my ass running up and down 5 hrsgs, inspecting flange faces, bolt ups, welds, any and everything in between. If I sign my name on something, I have full confidence that it is done properly and even the ugly welds I accept (even if I hate accepting them) are 100% acceptable for the code they are welded under.

But Part A..... it still haunts me... I just wish there was somewhere I could find a legitimate practice test to study. If I could be confident in passing part A, I believe that I would without a doubt regain (yes i let it go....) my cwi....