Started with 5x5. Made gains but didnt like how there wasnt enough accessory work to address my huge weaknesses (upper back, hamstrings/glutes, triceps, etc). 5x5 will make you stronger by the volume and frequency of the lifts, but sometimes the answer to a bigger squat isnt necessarily just to keep squatting, addressing the weak spot directly may be better.
Westside works. No other way to put it. But it isnt a miracle program, read Book of Methods and youll understand how crucial proper planning is. Personally, I ran it for a few months and it just pissed me off and I didnt make any gains, then I started training with several experienced powerlifters and my lifts took off.
With 5x5, you download a spreadsheet, plug in some 1 rms and go on autodrive. Westside isnt as easy.