I'm torn with how I feel about this era. For one, she looked amazing and was just so fun, fierce and happy. I loved seeing her giddy and taking so much joy in getting to know a guy and actually act like a young, carefree woman and not just a persona.
That being said, she was clearly immature and reckless and diving headfirst into a relationship that I don't think either one of them was really ready for. Kevin had a kid with one on the way and Brit was probably still hurting from a number of things like her breakup with JT, rumored issues with her parents and label, career pressures, etc. I just think the poor girl was severely overworked and socially underdeveloped at this point. Plus, and while I'm definitely no expert, this is around the age mental issues begin manifesting and revealing themselves in adults so we don't know what she was battling behind the scenes, either.
It also appeared like she was self-medicating with "party drugs" during the Chaotic era which is why some of her antics and general recklessness/"anti-Britney" behavior began to become amplified and raise some eyebrows. That being said, she was also young, dumb and in love and clearly wanted to blow off steam, have fun, shed her image and send one big f**k you to the media and her team which Kevin enabled. And why not? She really thought he was gonna be the one to save her. She found herself with a down-home, working class, struggling dancer who was so the opposite of who people envisioned for her and I feel like that was a major part of the attraction. He was rough around the edges and she wanted to be, too. She was so tired of being a product and I think she really found a piece of herself in him.
I don't like Kevin, I always questioned his intentions, but I also don't think he was solely to blame for everything that transpired after. I think it was an overflowing pot (full of vegetables? ) of all sorts of issues, pressure, heartbreak, poor mental health, unrelenting press, negativity and the general insanity caused by a career of her caliber. Sure, she made some really bad choices, and yes, she should be held accountable, but I also can't say I'm surprised she did. I would have been broken, too.
TL;DR: It did tarnish her image with the GP and subsequently increased the media attention on her for the worse.