I was using 5x5 for a few months, strength increased considerably went from dumbell pressing 70lbs to 100lbs in 3 months. Ive changed it up since then as I found that my strength was increasing but there was no muscle gains, I now implement hypertrophy exercises with heavy lifting. Take my leg day routine for example.
4 set of squats
set 1 (warm up) 132lbs 15 reps
set 2 (warm up) 176lbs 15 reps
set 3 (working) 264lbs 10 reps
set 4 (working) 308lbs 8 reps
4 sets of leg press
Go as heavy as possible in these getting 8-10 reps After doing heavy sets of squats you will not be able to go as heavy as you would have fresh. I consider my squat as my MAIN lift for power and this is an main/assist although I still go heavy.
The rest of the exercises are now assists.
4 sets of walking lunges. 44lb dumbells x 20 steps
3 sets of leg extensions. Enough weight to get 12-15 reps
lying leg curls. Enough weight to get 12-15 reps.
standing and laying calv raises 3 sets each. 20 reps.
Ive managed to really get maximum strength and muscle development from this structure. But different things work for different people. All about trial and error. Stick to a routine for 3-4 months at a time to really see if it works for you.