Lawyers at the Coollawyer.com, explain the legal "paradox" inherent in the LOI, wherein the signing of an LOI, is often prone, not to bringing about less litigation, but more litigation, and put it this way:
But intentions are not binding contractual conditions. Nor need they lead up to binding contractual conditions. Moreover a letter expressing intent, in its form, does not adequately suggest what the appropriate response should be. Whereas a Request for Quotation / RFQ quite literally is a Request. For a Price Quotation. Hence the document's name, it meaning is expressed by it's name. Hence an appropriate response, for a vendor or supplier, is issuing a a price quote.