If the PS3 is changing your programming techniques, then you will end up with a worse game on 360 than you would otherwise. The only time this doesn't apply is if you make the assumption that given the same resources, the absence of PS3 causes games to be created less optimally. That's a pretty lame assumption...
Except T.B.(also a developer) argues almost exactly that: the Cell-friendly approach helps with 360 games. His view (forgive me if I'm misinterpreting), which seems quite sensible is: the more restrictive Cell forces you to treat parallelism in a more constrained, more controllable way. This can be applied to the 360 as well, helping you avoid race conditions or other pitfalls, particularly when quick additions/changes to the code are needed.