Well, I have 4 Dell Mini 9s here and all are on 10.5.8. All are on BIOS A05, RUNCORE 32GB, and DELLEFI 1.25a.
â€¢ Battery indicator - no big deal...however, it is not the problem. The problem is as described in many threads in the forum...power manager is no longer there and we lost power management profiles. This might have no adverse affect for some people...for me, I have a power profile that accomplishes what I need the Mini for with about 4+ hours battery life and a profiles when it is connected to external display and power cord where I do not want dimming screens early, sleep etc.
â€¢ Not sleeping with lid close - 3 worked fine 1 did not. I found that I had to turn off USB Wake feature in BIOS on the 4th to make it work again. 10.5.7 worked fine with either BIOS setting. 10.5.8 does not. The symptom is when you close the lid, the LED blinks once like it is going to sleep...then it goes solid and is awake. Once BIOS changed, it blinks and goes to sleep as normal.
â€¢ Stability - I upgraded 2 Dell Minis from 10.5.7 and 2 new ones built from 10.5.6 upgraded to 10.5.8. All exhibit an infrequent stability issue. The signs for me are spinning beach ball, and the grey message screen to power off. I don't have all facts, but I suspect WIFI/network related. The 2 older 10.5.7 Mini 9s had been rock solid since day 1 of 10.5.7 upgrade, used and abused on a daily basis as much as the rest of the MacBooks/MacBook Pros. At the moment, it is not happening frequent enough for me to be of concern. Each Mini has had at least 1 failure each (since 10.5.8 intro day), 1 particular Mini (Sleep issue one) has had many panics and I had rebuilt it a few times from scratch until I figured out the BIOS issue.
Overall, it isn't enough for me to go back to 10.5.7 yet...but it may be better for some users to wait for all these issues resolved before upgrading.