Some thoughts from an old but fairly modern photog. First, credentials - pro + semi-pro photog since the mid 70s, pro computer programmer and consultant since 79 specializing in data compression tech. Below is a link to an article from the European Canon site that summarizes the lossless vs. lossy controversy very well. A quick synopsis is, RAW is compressed but in a lossless fashion. JPEG (or other loss-based compression methods such as PNG) are lossy and can easily result in inferior but more convenient image storage. Your job is to experiment and find the dynamic balance point between them on a shot by shot basis. The article does a pretty good (and accurate) job of describing this tech. Also, although from Canon, the tech description applies to pretty much all digital imaging technologies used by all camera software folks. Here's the link:

http://cpn.canon-europe.com/content/education/infobank/image_compression/lossless_and_lossy_compression.do

Hope this helps allay your concerns.