FYI guys, here are what's working now on N900 with Maemo Leste :

Calls (2G, 3G, 3.5G) (need better integration)
SMS
WiFi
Data (2G, 3G, 3.5G)
SIP calls and messages (TLS)
Social messaging (through libpurple or bitlbee)
FM Transmitter
Infrared ir-tx (custom driver needed)
HW acceleration
Overclock (850MHz actually, 1GHz might be possible)
GPS
Web browser (links2 gui mode) (TLS 1.3)
Video ( XV acceleration with Mplayer/SMplayer)
Audio (Pulseaudio and UCM)
Game Emulators (Retroarch) (Picodrive) (Pcsx-rearmed)
Youtube streaming and download (yt-dlp)
Almost all classic command line tools
Emails (imap4)
The last Linux kernel is 6.1.48 (2023)
And other things i don't remember.

In fact only bluetooth (+ fmrx) and the camera are not working yet.
Of course many functionalities need some better integration or need to be improved.

In my opinion, touch screen responsiveness is still slower than Fremantle but someone with transition.ini experience could help.