I have gtx260M, 32 bit system, kernel 32 and the card is "working" in the same way with the last stable nvidia-drivers or the beta 195.*
There are for me two main (and BIG) problem:
-the first is exposed here: http://www.nvnews.net/vbulletin/showthread.php?t=141116
and is about the switching to 3D frequencies.
-Second, when I start the laptop with battery power (even if later I plug the power supply, the card doesn't switch from Battery to AC despite the ACPI is working good) the X is very unstable and when crash the error is:
[13640.620325] NVRM: Xid (0002:00): 6, PE0001
The second issue is not present when alimentation is plugged in at the system boot; the first persists.
All my bug-reports are in the thread reported above