Model-Driven Engineering relies on collections of models, which are the primary artefacts for software development. To enable knowledge sharing and reuse, models need to be managed within repositories, where they can be retrieved upon users queries. This paper examines two different techniques for indexing and searching model repositories, with a focus on Web development projects encoded in a Domain Specific Language. Keyword-based and content-based search (also known as query-by-example) are contrasted, with respect to the architecture of the system, the processing of models and queries, and the way in which metamodel knowledge can be exploited to improve search. A thorough experimental evaluation is conducted to examine what parameter configurations lead to better accuracy and to offer an insight in what queries are addressed best by each system.