It's worked plenty well for a lot of people. The best thing about it (or any other reasonable program) is that is does give you a structure you can follow and use for a long period of time. I've always said that any program followed with consistency and dedication is going to work better than doing something different every couple of weeks.
The main drawback of 5/3/1 as it is written is the lack of volume on the main lifts, BUT some guys do really well on a little less volume.
Don't listen to all the internet bullshit. Like anything else....some guys have gotten great progress, some have not. The reasons people succeed (or don't) is quite a long list, much of which has nothing to do with the actual program.
Follow the program for 6 months, eat well, sleep well, and train your ass off and then re-assess at the end of 6 months and see what has happened.