is their actually any real advantage to upgrading your strategy building....if so what level does it need to get to. I don't see any change that makes it a benefit against upgrading other buildings

I would say it depends on your league level. A 10% gain when your stats max at 50 is only 5 points. But as you gain levels, and add another Strat building, the add will be double-digits and really nice. You can definitely see it when competing against players with 3 strats. But it is a slow gain, only adding .5% each upgrade, so hard to see a difference at first. If you were to ignore the building, but your opponents kept upgrading, you would find it harder to win.

It depends on your rank, but Kenneth, feel free to ignore your strat building if you're in single digits. I only upgraded it when it was far cheaper than my other "big" buildings until around rank 11.

In the higher levels it makes a huge difference, especially when you have three of those buggers maxed out