The two famous bows mentioned in the Mahabharata

VIJAYA : 

This bow was wielded by Karna. As the name suggests Vijaya means Victory, the bow was sure to give victory to the possessor. The bow Vijaya was specially made by Vishvakarma for Lord Shiva to  destroy the city of Tripura built by sons of Tarakasura. Lord Shiva  destroyed Tripura by firing Pashupatastra from Vijaya. . This bow was then given to Parshurama by Lord Shiva along with many other celestial weapons for killing all the Kshatriyas in the world. The bow was given to Karna by his teacher Parshurama. It is generally believed that the string of the bow was unbreakable and created thunderous sound and lightning, causing fear in the hearts of enemy, each time an arrow was released from it.

After the death of Karna, Vijaya bow went back to its original owner, Lord Parasuram.

GANDIVA : 

This one was possessed by Arjuna. It was forged by Lord Brahma himself. The bow was itself created from an heavenly tree called Gandi. The bow was so heavy that it could be wielded by only few people. The ownership of the bow passed on to various people. It came to Arjuna from Lord Agni when he wanted to devour the Khandava forest. The bow was known to create deep rumble and produce lightnings every time it was used creating trouble for enemies. It could fire hundreds of arrows at a time and at over great distances, making it one of the most formidable bows.

Note : - Out of both the bow's Vijaya Bow is very powerfull.