Alright. What we know of both.

Vibranium: is extremely durable, due to (simplifying it) it absorbing the force and dispersing it through its molecular bonds. But has the weakness that it can be destroyed by enough force.

Saber cloth: Can't be pierced through, or truly damaged in any known way so far. Absorbs energy and disperses it, but can be overloaded by an incredibly excessive amount of energy. But does not stop force, meaning that ballistic weapons will turn insides to mush even without entering the body after a little bit.

So, we know that not even mjolnir can break vibranium. However the fact that with how much force was applied, the hammer did not shatter, we can assume that the shield and the hammers materials are just as strong as one another. This provides a good base. This means that an excessive amount of force is needed to damage vibranium. However the amount is not out of human range to do so. So to find about how much Vibraniums breaking point is, we would need to know how many and what type of bomb was used to destroy the vibranium island.

So, we need to use an educated guess. The standard missile used by the American government is the tomahawk cruise missile. It has a power of about 1000 tons of TNT. And America has a maximum of 3500 in stock. So, we know that the explosive force applied to the vibranium has to be either above 1.2 million tons of TNT (approximately the force that was let out when thors hammer exploded in a comic) or equal to or below 3.5 million tons of TNT. There fore vibranium is able to withstand the force applied in an exploson with an explosive force anywhere between 1.2 and 3.5 million tons of TNT.

Saber cloth on the other hand is shown to be able to survive explosions unharmed. While the same can't be said for the person wearing the Saber cloth, the cloth itself will remained undamaged. This is used by applying what I call the kolon tests. In which Kolon actually attempted to blow up Saber cloth. His nukes are typically up to 10 million tons of TNT. So we can assume that Saber cloth has more survivability then vibranium. But less defensive capabilities for the wearer, since the force applied is still applied to the wearer, rather then taken by the cloth itself.

From this quick study, we can assume at a glance that vibranium is much weaker then Saber Cloth, but has its own advantages that puts it on par with Saber cloth. Which I will list below

Vibranium:

Advantages:
More variety: Vibranium is both an extremely durable material, and an incredibly flexible one if it needs to be. A user can have both strength and flexibility, while covering both the physical and energy based weaponry bases.

Weaknesses:
Vibranium has a merely average breaking point when compared to the multiverse, where characters can dish out more then enough damage to overload the molecular bonds and destroy the vibranium.

Saber cloth:
Advantages: Saber cloth has a much higher level of durability then Vibranium. With soft Saber cloth being able to withstand a known force of 10 million tons of TNT. And possibly more since it has never been tested above that. Making it virtually indestructible

Weaknesses:
Saber cloth lacks Vibraniums versatility. It can either be soft, and offer little protection to the wearers internals. Or it can be Hard and cumbersome to move around in.

As weapons:

Vibranium:

Vibranium is shown as a weapon multiple times. For the most part they are decent weapons, with some even being able to liquid other metals

Saber cloth:

Often used as swords, Saber cloth can be compressed into a lightweight, very dense material called hard Saber cloth. Hard Saber cloth has the disadvantage of lacking any flexibility. But the advantage of being incredibly hard, incredibly dense, and is capable of being sharpened to an incredible amount.