Overdrive is good actually...I still use it with my 965...
All I know about the 1090T is that AMD updated OverDrive after the release of the new 6-cores, giving new features such as Turbo Core control I think and stuff so I think yeah it's still suggested.
I guess it just depends on how you want to go about it. The more tried and true method would be using the BIOS but as you can see, Overdrive does well for some.
The last time I used Overdrive, 4-5 months ago, AMD introduced severe limits in how far you could push the chip. I don't know if they've removed those lately, but it was enough to make me switch to BIOS only over-clocking. Before , I used AOD to adjust the clock speeds according to what I was doing at the time.
@SicKlown42012: They've removed the limit and put them back now on the latest version, but I still use the older one because there is no limit on how far you could push the chip, unlike the latest version.