For my 5770, phoenix is the only one that reaches speeds of 218.00 MH/s. All the others lag behind.

I am currently using the svn version, and launching it as follows:

LD_LIBRARY_PATH=/opt/AMD-APP-SDK-v2.4-lnx64/lib/x86_64/ python phoenix.py -u http://user:pass@host:port/ -k phatk DEVICE=0 BFI_INT VECTORS FASTLOOP=false AGGRESSION=13 WORKSIZE=128 -v

I suggest you play with:
- whether sdk 2.1 or 2.4 is best (if you use phatk, you need 2.4)
- whether VECTORS makes a change for you or not
- WORKSIZE depending on the card either 128 or 256; despite what the wiki says, I get better speeds with 128.
- the speed of your memory -- despite common claims, for me 960 was the best rather than 600 (although I could not go lower than 600)

Not too shabby:

$ aticonfig --odgt --adapter=all
Adapter 0 - ATI Radeon HD 5700 Series
            Sensor 0: Temperature - 73.00 C
$ aticonfig --odgc --adapter=all
Adapter 0 - ATI Radeon HD 5700 Series
                            Core (MHz)    Memory (MHz)
           Current Clocks :    960           960
             Current Peak :    960           960
  Configurable Peak Range : [600-960]     [600-1445]
                 GPU load :    99%