"no better either" is correct and usable in written English.
It is used as an idiom and is a way of saying that something is no better than the other option. For example, "I don't like either of the two options, but the second one is no better either."
So far the synergies are not overwhelming, and ABC is doing no better, either financially or in the ratings.
But it's no better either.
Yet Lièvremont's relationship with the media is no better, either.
But unless the mothers' incomes rose, they did no better either.
One atrocity is too many and while the British were no more atrocious as imperialists as anyone else they were no better either".
By day I was chained to my desk, expected to provide a hair-trigger response to any barked command, and nights were no better either.
"Expert Political Judgment" is just one of more than a hundred studies that have pitted experts against statistical or actuarial formulas, and in almost all of those studies the people either do no better than the formulas or do worse.
"I am no better than Armstrong, but no worse either.
Although Mr. Romney captured more than half of all votes in Nevada's caucuses, he received only one in three votes of those earning less that $30,000 a year — no better than either Mr. Gingrich or Mr. Paul.
The resulting high-quality RCTs corroborated the general finding that "arthroscopic surgery" is no better than either physiotherapy or sham surgery in patients with various degrees of knee OA and meniscal "tear" (Herrlin et al. 2007, 2013, Kirkley et al. 2008, Katz et al. 2013, Sihvonen et al. 2013, Yim et al. 2013).
Most of the new stocks did no better than hold steady once they started trading, either.
