I prefer Canon's DPP for conversion, the latest version (3.4.1.1) added several improvements and increased the number of lenses for which it can correct aberrations. In terms of color fidelity, DPP seems to do a better job with the reds & yellows. Although DPP can do a direct transfer of the converted file to Photoshop if desired, saving the file in PS is a bit of an annoyance as the default folder is a 'temp' and it takes a lot of mouse clicking to designate a different folder.
I also use ACR due to its seamless integration with PS and the overall performance. If I don't have a lot of yellows or reds, I tend to prefer ACR. I also like ACR for recovery of blown highlights and pulling detail from shadows, I'm constantly fighting this with bird photography. There is a beta version of camera profiles and the DNG editor for ACR 4.5 available via the Adobe Labs website that improves the color renditions. I just installed it but haven't done much in terms of comparisons yet. My initial impressions are good and it looks promising.
http://labs.adobe.com/wiki/index.php/DNG_ProfilesI've tried several other converters - of the ones I've tried each has strengths and perhaps weaknesses. I haven't found one that provides compelling enough reasons to switch. I'm not looking forward to the prospects of converting my RAW files to DNG or another format. I hope Canon & Adobe maintain compatibility with earlier formats.