This is brilliant.
Having recently upgrade my AV system I was always switching between controls to get it 'just so'. We had 4 normal controls, TV, Sky, PS3 remote and AV amp. We now have just one.
Activities work well, watch TV = 1 press and the Harmony turns on the TV, Sky box and Amp and switches everything to the correct channel. Press play game and it changes everything to the correct channels again.
Easy to set up and easier to use than the 4 controllers we had before.
Just one final note, if you use the ps3 for DVD then you will need the PS adaptor as this is IR only not bluetooth. That's not a critisism of the Harmony but of the PS3.