I use it as my main raw convertor. It does an excellent job on Fuji files, and has replaced Photo Ninja as my convertor of choice. It also does a very good job on nefs, but I have not actively compared this with other convertors.
The program was a bit buggy when first released, and I made a detailed report to ON1. They have since released a couple of updates, and it seems stable. ON1 are very active in communicating with users, and upgrading the software, unlike Photo Ninja.
Converted raws can be moved directly into Photoshop, but the program automatically creates a psd to achieve this. Fortunately, the user does not have to create the psd and open it in Photoshop - the process is automatic.