Having invested in 22 Europe->U.S. companies, I am not sure the differences are all that huge, absent cases where there are regulatory differences.
But in SaaS, there are fewer veterans in Europe than the U.S. This tends to mean more stretch candidates and more risky candidates for Directors and VPs. It also tends to mean worse training for more junior candidates.
Surprisingly, turnover can be just as high in Europe among more junior candidates. This can meaningfully drive up the cost of employees vs. U.S., even if salaries are 1/3d to 1/2 of SF Bay Area.
Having said that, there are far more veterans in Europe than even 24 months ago. And the U.S. HQ’d SaaS companies all have bigger outposts and European offices than they used to, that you can poach from.