Virtuoso SPARQL Query Editor at http://dbpedia.org/sparql is very similar to SNORQL. It offers additional export formats like Turtle, RDF/XML, CSV and others. It has also more predefined namespace prefixes. However, the results are displayed on a separate page. Therefore I prefer SNORQL, where it is easier and faster to tweak the query.
OpenLink Interactive SPARQL Query Builder (iSPARQL) at http://dbpedia.org/isparql is an advanced query builder with many features. It helps you to write queries by choosing from predefined templates. There is also an option to build a query visually by constructing a graph, but I find this method confusing. There are more ways how you can display results. In addition to grid view there is also some kind of chart. iSPARQL may be useful for intranet portals, because you can save your queries to a WebDAV server which you can browse and run later. I personally find iSPARQL very unintuitive. Source code is available on github.
DBpedia Query builder at http://querybuilder.dbpedia.org is very simple tool. It shields you from directly typing in the SPARQL query by providing inputs which are translated into a WHERE clause. It is very limited and I do not find it practical at all.
Faceted Browser at http://dbpedia.org/fct is an alternative way how to query the data. The advantage is that user does not have to know SPARQL. First a search box is present and the text query matches among all values and attributes. One can view matched entities, attributes and values including their frequency count. This can be used as a facet and refine the query. The final query can be exported in SPARQL. I like this approach, but I think the UI can be even more intuitive.
From the tools described above I prefer to craft the query using SNORQL. Faceted Browser can be sometimes used to speed up the creation of initial query. However, I conclude that none of these tools are suitable for a common user and better tools must be developed.