Still in process of switching entire house and exterior to CFLs.
Thus far, I've run into these behaviors on different 13W (40W resistance lighting equivalent advertised) CFLs.
Lights in hallway and front porch- half second delay before any illumination at all. Relatively dim illumination to the others mentioned here. Makes me nervous without instant lighting.
Hollywood style lighting over sink. Immediate turn-on, practically no wait time for full illumination.
Recessed lighting in kitchen- takes about a minute before full illumination. Quite bright when that time expires. No time delay for some initial illumination, but, very dim initially. If switched off, and immediately turned on, full illumination is there right away.
Believe they're all GE make. First set bought at dollar store. 2nd and 3rd sets bought at Ace Hardware.
Why the different turn-on and illumination behaviors?