I'd say it depends what you want to do. It's way better at organising, storage, lookup etc than iPhoto and similar programs, although many think Aperture is better.
In terms of developing, early betas were shaky with regard to sharpening, noise reduction and the like. The V1.0 release was better, and the V1.1 is a significant step forward in many areas, updating camera raw to include clarity control, adding much improved sharpening etc.
I personally really like it. No, it won't do everything CS3 can do, nor is it as good as noise-ninja at noise-reduction, but it does give you 90+% of what those products can do, and all in one package. And with management, filing, web output, slideshows etc thrown in.
It can be resource hungry if not set up properly, or if computer is older, but I run it fine on my old 12" powerbook, which is not the greatest in terms of CPU, GPU or RAM.
Best bet is to download the demo and give it a try - I believe it's fully featured for thirty days. If you have any questions though, I can try to answer them.