I normally go Repti Glo, but went with Reptisun linear because of availability. The new bulb seems to slightly pulsate. Don't know if anyone else has encountered this, or if it's a bad bulb.
My fresh bulbs will pulse/dim for the first few hours/days i use them till they break in. Electronic ballasts will get rid of the pulse/traveling wave problem/blacked ends, but wont get rid of the dimming.