Why not just use Google?
A Google search will work fine is you know exactly what you are looking for. It will also work ok for judgements which are rendered in html or other readable format, but not for non-readable pdfs.
eJudgements tags all new judgements (and is in the process of doing the same to historic ones) with metadata which ensures that you will be able to find relevant cases. The metadata tags also assist with ensuring the relevance of normal searches.
Whereas a Google search will give you a list of cases which you then have to trawl through one-by-one, with eJudgements you will be able to narrow your search as you go and also use the graphic interface to scroll through the document without having to first open it to see if it is relevant.
eJudgements also adds other tags, for example whether a case was overturned on appeal, which will not be found on a Google search.