So far I have not had any problem with the beta.
I'm not sure I like the new interface.
PhaseOne is still underestimating the value and the need of decent documentation/help files.
I'm dearly missing the renaming feature (or did I miss it?)
On the positive side it's way way faster than 3.7.
I can understand why many will prefer LR and I think PhaseOne is still underestimating the damage it will suffer as a consequence of taking so much time for so little. Although I still think C1 produces better files and notably better colors than LR.
Ideally, they would license their RAW engine to Adobe for inclusion in LR.
Or they would buy an Adobe license for LR's library management technologies to integrate them into C1.
While they're at it they should license Nikon's high ISO denoising algorithms so that we can truly use high ISO with digital backs