Just my opinion:
I started 5x3x1 about 9 weeks ago. One of my main issues was just not doing the compound movements enough to gain confidence and experience in them to get comfortable with the technique at heavier volumes. Although i would not win any comp's, the way the program is set up lets you get good work in with the ability to have perfect form.
That is crucial. Your first 2 sets of every compound movement are at a % that you can be technically flawless and still get great work in. The 3rd set lets you really push yourself. The assistance work does not waste your time, and is actually designed to get you stronger. Overall, i am really excited i took the chance and committed to this routine, as i am getting stronger, but more importantly, improving my technique.
My only advice about the 5x3x1: Commit whole-heartily and bust your ass everyday. if you do that, and eat your wheaties, you will see results throughout, especially as you get into it and start setting PR's.