I made an experiment. Switched off my N900 and my Jolla and made some measurements. All are accurate to +/-2 seconds, due to using a regular wrist watch and having to constantly flip between looking at the watch and the phone screen.

First, the N900:
12 seconds of white screen with the Nokia logo, then darkness
35 seconds to the wallpaper first appearing
55 seconds to first desktop icons appearing
1 minute for the desktop fully populated
1 minute 5 seconds for tapping on the File Manager icon having any effect
1 minute 17 seconds for File Manager actually showing any mounted volumes

Now the Jolla:
15 seconds of Jolla logo, then darkness
35 seconds to the first sign of any life (spinner)
50 seconds to the home screen
To Jolla's credit, I could use the phone from that point on.