What is the strength level of Madara's Susanoo? Madara compares his Susanoo with the Tailed Beasts. We also know at one point of time, the 3rd Raikage had a chakra level comparable to that of a Tailed Beast. However, the difference in power of Madara's Susanoo and chakra level of the Third Raikage is huge.

So how do we comprehend the power level of Madara's Susanoo?
Let's take a look at some instances where Madara manifested his Susanoo's power:

It can summon 2 meteors simultaneously which resulted to complete chaos.
His clones can summon Susanoo with ease.
His Complete Body - Susanoo is gigantic.
It can take down 5 Kages easily.



Tengai Shinsei
Madara's Susanoo on Narutopedia

Having awakened the power of both his Mangekyō, Madara could use Susanoo. He did not need to fully manifest it to benefit from its use: with just its ribcage he can withstand an Ultra-Big Ball Rasengan, and he could perform attacks with only its upper half. [...] His Susanoo wielded up to two (four in the anime) undulating blades that could be thrown, then maintained and controlled remotely. Madara can also produce Yasaka Magatama of varying sizes.
[...]
According to Madara, the full power of his Complete Body — Susanoo was comparable to that of the tailed beasts, and no one had lived to see it a second time. Madara was able to shape his stabilised Susanoo as an armour which he equipped unto the Nine-Tails in order to complement their respective abilities.

So is there any way to break his extraordinary defense?

 Yes. The increased defensive strength of Madara's final Susanoo's form can only be destroyed or even pierced by powerful techniques like Hashirama's Top Transformed Buddha [Ch. 626].

Quoted from old version of Madara Uchiha on Narutopedia