2011 Mini i5 2.5GHz, 8GB RAM, 128GB SSD
ca. 22sec from pressing power-button to desktop (password entry included), the time varies a bit.
The SSD made a HUGE difference in startup time as expected.
Swapping the HDD for an SSD was quite easy even though my SSD is quite "bulky" and needed some wiggling to get it in without removing the logic board.