To be clear, I have not paddled a Phoenix. I had the Guide for years and now I have the Wildfire. Both of those are almost as long as the Phoenix, but with symmetrical rocker. They are both easily class 2+ capable. The Phoenix is said to be similar in river worthiness to the Wildfire but easier to track straight, due to the lower stern rocker and additional ~6" length. I was able to paddle the Guide straight on flats, and it's easier to do so in the Wildfire. But I assume the Phoenix will track easier. As a note - I paddled the Sojourn successfully in non-technical class 2, and it's a hard tracker. Not as enjoyable though and demands a bit more attention.
All of this makes me confident that the Phoenix should be a great all-around solo for lakes and rivers up to class 2+, and higher for a skilled paddler.