What is the essential difference between revoking acceptance and bringing a suit for breach of contract?

Under the UCC, a buyer or lessee who has accepted goods may be able to revoke acceptance under the circumstances mentioned on pages 348 and 349. The United Nations Convention on Contracts for the International Sale of Goods (CISG) also allows buyers to rescind their contracts after they have accepted the goods. The CISG, however, takes a somewhat different—and more direct—approach to the problem than the UCC does. In the same circumstances that permit a buyer to revoke acceptance under the UCC, under the CISG the buyer can simply declare that the seller has fundamentally breached the contract and proceed to sue the seller for the breach. Article 25 of the CISG states that a “breach of contract committed by one of the parties is fundamental if it results in such detriment to the other party as substantially to deprive him [or her] of what he [or she] is entitled to expect under the contract.” For example, to revoke acceptance of a shipment under the CISG, a buyer need not prove that the nonconformity of one shipment substantially impaired the value of the whole lot. The buyer can simply file a lawsuit alleging that the seller is in breach.