If, even after climbing at best rate (turbulent speed), ATC says "Expedite Climb", is it advisable to climb at best angle (GD), or just tell them that it's the best you can do.
Well said Zonoma; communication: To Matthew; it's team work. I agree that a request to 'expedite' is imprecise and open to guesswork. Just ask ATC what they want. They have a plan in mind, but you don't know what it is. Their meaning of expedite might be different to yours. They'll want to have you crossing a level by such a point or time. They may not have run a computation at your current ROC. They just want to ensure that you'll achieve a level within their plan, hence expedite. Find out what the goal is and then advise if you can achieve it. Also have an answer as to what you can achieve at the critical point/time then ATC can work around that. They can vector you, issue a re-clearance level, or shift the other traffic. It may be the call is to achieve a standard silent handover level to another sector. If you can't make it ATC can liaise with that sector and find out what is acceptable.
Rather than second guess ATC use good CRM and ask a question to help the team work with effective teamwork.