Ollie has had her light since around November (I think

)- so for around 10 months or so. I really didn't/haven't noticed any big behavioral changes. She was ~6 months old when I got it, so any changes I saw could have just been her growing up.
She loves to sit under her light. She does seem quieter when she's in her cage under the light, but that is probably just because she is really only in her cage for a few hours during the day (when I'm not here to observe her) and then in the evening when she is preening and getting settled in for bed time. So she gets most of her playing and talking accomplished outside of her cage on her gyms.
She looks very healthy physically, which I'm sure is due in part to the lighting. I'm sure having a bright light like that over her during the day also does wonders for her quality of life! Its as close as I can give her to being under the hot sun outside!