If you are mainly looking for a RAW converter, there are many options available at various price points and degrees of competence. The free convertors are particularly attractive, though it should be noted that almost all are built on the
dcraw convertor. The prominent exception is RawTherapy which uses an extension to dcraw. As a result, the main difference between the free convertors is the sophistication of the user interface and file/image management.
In regards to competence, there is a wide variation in the quality of results available from the available convertors. It may seem strange, but to be honest, some simply suck. What is more, comparable images may not be possible between convertors. I suggest trying before buying and evaluating with a RAW file having known characteristics.
FWIW, I have tried the competition and have stayed with Lightroom for both RAW conversion and image management.
Steve