There are all sorts of reasons for incorporating and most of these are unchanged but two things have changed or are about to change.
1.Corporation tax increases combined with National Insurance reductions mean that the level and which it is tax efficient to incorporate have increased to around £100k* profits
2.At the moment small companies do not have to publish full accounts at Companies House. In future they will need to show their profit and loss account. This means that sensitive commercial and personal information will be in the public domain. For sole directors their salary will be available for anybody to see.
There may still be reasons, tax and otherwise, why business may choose to trade through a limited company so personal advice is more important than ever.
*This is a guide and the actual level still depends on individual circumstances.