The only thing I didn't like in Phase One was the lack of dedicated a dedicated fill light control, but I used to prefer the output to LR3..
Workflow wise, I always kept going back to Phase One over LR3, and things haven't improved in LR4 much in that respect, you still have the totally seperate library/developer thing going on and have to import everything in a slightly clunkier manner etc, which is fine for some..
But I did like LR4's newer developer stuff, it's a nice step up from LR3, and in some ways an improvement over Phase ONE (The only thing I hated in Phase One was no dedicated fill light control!)..
But, I've actually moved over to the very cheap Corel Aftershot Pro ($60) a.k.a. Bibble Pro.
This is lightening fast in comparison to even LR4, and also allows the most flexibility for working with either libraries or just a file view.. It's got layers/local adjustments and even comes with Noise Ninja (standard version) for free. The only dedicated control it lacks is clarity, but there are many good free plug ins that provide that, I also found the wavelet denoise and wavelet sharpening plug-ins work really well, and the way the plugins are structured, they work seemlessly with all other adjustments.
Just food for thought, I'd download demo's of them all, and see what suits you.. I have my own criteria which is why I went with ASP in the end, but I only did this after trialling it against the others..