I will not develop here the pros and cons of this software is found enough photographers sites to talk much better than me. I bought Ligtroom 5: -First to "develop" my RAW files because it is one of the best tools to do well over that of Camera RAW included in PES. Particularly for its finesse and processing power whether on the whole image or specific areas. Localized treatment that does not exist the Camera RAW PES (I V9). Often it is not necessary (although easy) after treatment Lightroom go through PSE, which required with Camera RAW. -in second place for cataloging my images once they have been managed and "tagged" (metadata) with a great tool XnView MP. Indeed the latter, very powerful for entering XMP or IPTC in its latest versions, does not offer a real "cataloging".
Note I had version 5.0 CD while V5.3 is released. It is therefore the download especially if you have a camera or recent goal and we want its characterstics are taken into account in the possible automatic corrections of defects
