5x5 can certainly be good, but I'll note that there are dozens of popular 5x5 programs out there, and certainly hundreds of 5x5 programs have been written throughout the years. I see you've already been referred to Stronglifts 5x5, which I've never tried and don't know all the tiny details about, but see no reason why it would be problematic.
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Just for your information, "5x5" - as I've already said - doesn't refer to just one program. As such, one 5x5 program may be quite effective...another not so much. Here are a few different interpretations of what 5x5 means - and for each different interpretation there are many different programs written:
5x5 ramping: 5 sets of 5 reps, starting at a light weight and working up to a heavy weight. Bill Starr's programs often use this method with the following weight progressing (from set to set):
1st set: 5 x 50% top set
2nd set: 5 x 62.5% top set
3rd set: 5 x 75% top set
4th set: 5 x 87.5% top set
5th (top) set: 5 x 100% top set
5x5 across: 5 sets of 5 reps at the same weight, generally following several lighter warm up sets. This might look like:
Warm up: 2x5x20kg, 1x3x40kg, 1x2x60kg
Work sets across: 5x5x80kg
5x5 pyramid: 5 sets of 5 reps with the top set in the middle, and progressively lighter sets on either side. This might look like:
1st set: 5x50kg
2nd set: 5x60kg
3rd set: 5x70kg
4th set: 5x60kg
5th set: 5x50kg
5x5 waveloading: 5 sets of 5 reps at varying weights, increasing or decreasing weight with every set. This might look like:
1st set: 5x60kg
2nd set: 5x55kg
3rd set: 5x65kg
4th set: 5x60kg
5th set: 5x70kg
5x5 descending pyramid: Start with a weight that will be very difficult to perform for 5 reps. This weight should be very close to your 5RM (and might even be your 5RM). Perform your first set. Decrease weight slightly, rest 1min, and perform another set. Keep this up until all 5 sets are completed. This might look like:
1st set: 5x100kg
2nd set: 5x92.5kg
3rd set: 5x90kg
4th set: 5x87.5kg
5th set: 5x85kg
These different methods are also often intermingled. For example, Reg Park made famous the method of ramping up the weights until the 3rd set, then doing sets across, which might look like:
1st set: 5x50kg
2nd set: 5x60kg
3rd set: 5x70kg
4th set: 5x70kg
5th set: 5x70kg