This may be a little late for your decision, but I can give you my experience. I recently passed the new 16 hour SE exam (building exam for essay portion.) I highly recommend taking some type of review course for this extremely hard test. I took the School of PE review course for the vertical test and passed on the first try. I seriously doubt I would have passed without taking the course. The course is a large time commitment, but a lot of topics are covered. Each subject matter is taught by a different professor (some professors are better than others.) I would still highly recommend this course for a thorough review.
For the lateral test I couldn't commit to the time requirements for the School of PE lateral review, but I signed up for the Kaplan SE lateral review (the archived one was a little cheaper and I could take the course at my convenience.) This was a good course too. I passed the lateral on my second try.
Both courses have their positives and negatives. It's kind of a toss-up to choose between the two.
This is a very difficult test. You have to be all in. Do everything possible to pass the test on the first try. Buy every book you think you need and take a review course for each test. Studying for the test is a big time commitment. Unless you are very experienced in multiple subject matters, then passing is very difficult. I bought a lot of books to study from, but some of my most helpful are: Structural Engineer's Reference Manual 6th ed by PPI, PCI Design Handbook has a lot of good quick reference charts and lateral load design examples, SEAOC Structural/Seismic Design Manual Vol 1 & 2 (vol 1 is a must for the lateral test and vol 2 helped me with wood detailing since I don't have much experience with wood, NCEES Sample questions, and 16-Hour Structural Engineering (SE) Practice Exam for Buildings by PPI is GREAT.
I would recommend only taking one test at a time so you can properly study for that one test. Also, don't get discouraged if you fail a test, they change the type of essay questions for each test. So you just have to wait till you get the questions that you are able to do well on.
Good Luck.