I had one for a year or so.
I wanted a hardcore hardtail, and started off with a Rock Lobster B-52, which was made my Kinesis and was pretty much a Pha5e in all but name. Like others have said, it was quite short in the top tube, so I then sold that to get the Pha5e in the next size up.
It was a very good frame. Strong as an ox, but pretty lightweight. The only real complaint I could have about it would be that it was just too stiff and unforgiving. I found it was essential to run a high-volume tyre on the rear and keep it at around 30psi to soak up some of the trail buzz, otherwise every grain of dirt could be felt through the saddle.
A travel-adjust fork would be useful for dropping the front end down on climbs. With the fork wound down to around 120mm, it climbs very well indeed. At 140mm it descends really well. I used a RS Rev U-turn, and it worked very well.
Being the grass-is-always-greener type person, I swapped the Pha5e for an mmmBop, which was another step-wise improvement in handling and comfort, and then onto a Carbon 456. The Carbon 456 is what I'll be sticking with.
Will see if I can find some pics.