[icedchai]

Yes, the key is to never make ultimatums, as that creates too much conflict.

Just say you're "unhappy". Keep it vague. See what they do. It's tough finding good people in this market.

[Kalium]

Ultimatums can be useful both for cutting the negotiation process short (to avoid pain from inferior negotiation skills, for instance) or to show your business understanding. If you want executives to respect your business acumen, demonstrating your skills like this is one way to go about it.