I've spent the last week trying to get the RC working. I started with fresh install and ext4/encrypted home directory. It appeared to work but locked within an hour. (hard lock sometimes with caps/number lock flashing)

I noticed they had a problem with deletes in ext4 and so reformatted to ext3. Then I got kernel oops with what appeared to be the encrypted home directory stuff. So I turned that off as well and still was getting lockups. After days of reading bugs with the kernel 2.6.28, nvidia 180 drivers, and the intel 4965 wireless, I've still not solved the problem. It's hard to troubleshoot as there are no logs and the system is dead even to sysrq commands. I did see an issue with the hpet having problems, so I tried the other modes such as jiffies. Even used noapic/etc trying to get a stable system. Nothing seems to work. Funny thing is that 8.04 and 8.10 were rock solid on my system.

In many cases, running firefox and trying to watch flash video causes the lockups. Sometimes in less than five minutes.

Just FYI for anyone using similar hardware
Dell m1730
Intel X9000 @ 3.4GHz
4gb RAM
dual SSD 64GB RAID-0 (dual boot with XP)
dual nVidia 8800M GTX (SLI)
30" Dell LCD @ 2560x1600
Intel 4965 Wireless
Ubuntu 9.04 amd64

For most users, no it will not work. One of the major features of ext4 is extents, which basically reserves space for a file to continue writing at a later date. This will decrease file fragmentation and improve performance.

If however, you disable extents, then yes you can mount it as ext3. And as you know, ext3 can be mounted as ext2 without the journaling.

I agree that the win32 ext2 drivers need updating. I would hate to lose access to ext partitions for dual boot systems.