Afaik some if the best players play with horrible mice, at least according to this forum, and still own. I'm thinking of those playing with Kinzu's and such.
I did the delay test in TF2 with 450 and 2300 dpi, switching between 1.6 and 0.3 sensitivity to keep overall sens the same. There was a difference, but that could have been the smaller jaw and pitch, didn't feel like delay at least. I can't really say 2300 felt any better. Somehow 450 felt snappier to me, so I kept that.
Keep in mind I'm gaming on a 60 Hz screen, so my overall delay is probably bigger than for those of you who game on 120 or 144 Hz.
Anyway: if you feel comfortable with a setting just keep it and don't listen to forum hypes. Asking for advice only really helps if you feel that something is wrong. Otherwise it will only make you feel insecure about your setup which doesn't help either.