Why would there be a difference? They're both liquidity events.

Both parties have a lot more flexibility with M&A (this includes vested partners) — meaning private deals have far better conditions if the deal isn't a saving grace.

IPOs can have lengthy lock up periods and are generally much worse for leadership than acquisition (disclosure of personal information like compensation).

180 day lock up probably for employees mostly.. maybe founders are included in that.

IPO's tend to be bigger paydays even if they are more risky so I would assume they prefer IPO's.