Volume: This whistle is medium-soft. In a medium-sized session, you really can't hear it.
Responsiveness: This whistle is not very responsive. I have always had trouble playing fast tunes on this whistle. I know it's not me, or my non-piper's grip, because I've had no problems playing fast tunes on the Alba low D, the Copeland low D, and Phil's newer model low D which I was able to play once at a session when someone showed up with one. On this whistle, you get above a certain speed and tunes start getting muddled. But it's great for slow and even medium-fast tunes. [I own a new range Chieftain low D now, and it's definitely more responsive than this one was.]
Tuning: This whistle is in tune when warmed. That said, it takes a whole lotta warming up to keep it in tune. When I've played this at gigs, I've kept it under my butt, or tucked into my armpit to keep it warm. Let it sit for even a few minutes, and it's completely cold again. I know Phil has gotten some complaints about how much warming up his whistles take. I don't know if he's addressed this in the new models. [He has. See new-style Chieftain review.]
C-natural: OXXOOO produces a slightly-flat c-natural on this whistle..about 15 cents. OXOOOO is perfect.
Hole size and placement: This whistle has holes are on the large-ish side. The last hole is a little far from the pack, and I think some people might have trouble with this even with piper's grip. I use my pinkie on the bottom hole on all low whistles, so it's not a problem for me.
Air volume and pressure requirements: This whistle is very easy to blow in the first octave. As you move up the scale, however, the it takes more and more push to reach the note, especially as you get over 2nd octave G. Because the whistle has a very narrow windway, this makes for a large amount of back-pressure, which means that it can take some confidence to really play this whistle. Because the windway is so small, it doesn't take much air volume, however.
Clogging: As with the Alba: "Big metal whistles get wet. Fact of life." With a windway this narrow, the Chieftain clogs fast. It's not as bad in Dallas where the air is drier, but it's still a concern. I couldn't play lots of tunes in a row on this whistle. In Houston, this whistle was good for two in a row without clearing, if I was lucky.