What races besides humans would you say gets a massive PR boost?
All subjective to me, but a list off the top of my head:
-Turians possibly
-maybe or maybe not Salarians
-Krogan at least initially (depending on choices)
-Geth and/or Quarians (depending on choices)
-Rachni (depending on choices)
-Batarians (not the Hegemony)
But by 'boost', I mean 'much better than before'. Batarians may still be around the bottom, but in their case their government has collapsed and ever since then, we only see examples of individual Batarians making a good showing, as well as acquiring plenty of pity for their predicament. DLC War Assets of Batarian politicians rallying their people to work with the galaxy, and even the crazy Omega preacher taking a relatively cooperative tone to unite Omega against Cerberus (still anti-Human racist, but focusing on something else).
Most of boost came to the outcasts, and the top dogs got their humble pie in some way. Even with all the Turian contributions and the huge respect they'll get for that, they also showed that they are definitely NOT the necessarily absolute military superpower.
Salarians didn't get much one way or the other, from what I can tell. They both tried to stay out of things like Asari, but also came to/or could come to aid for the war earlier than Asari. As far as we can tell from info so far, they also didn't have anything in particular that either helped things a ton, or harmed things a ton (arguably, even the Prothian beacon stuff for the Asari, if it gets made public, would be a huge PR disaster in itself). They're problematic but they also didn't as actively hamper the situation as the Asari hiding out. While it seemed the majority of Matriarchs settled on waiting too long for consensus, the Salarian government seemed like a mix, many of which did support the war and helping it earlier.