WERS has professional-level radio production, solid music that has broad appeal without being "mainstream". Emerson is one of the few schools I know of where some people will go to the school specifically for the radio station. It's why they have such a large, consistent listnership.
WMBR's DJs are fantastic. The station itself definitely has a more college feel but it's still very well-produced and the station itself seems to be really good at playing obscure tunes, especially in the psych/garage/punk/shoegaze realm. There's a distinct sort of sound I expect with them that almost reminds me of WFMU where I grew up, which is high praise.
WHRB tends to favor classical and jazz more than the other schools' stations because they dedicate large blocs of time to those genres
And then there's my WRBB. We sometimes had some gaps in production (depending on who was DJing) but it's still a great listen since there tends to be a wider range of tunes that come through the station. It also helped that many of our DJs were stalwarts of the local DIY music scene, so we gave airtime to a lot of small local artists that might not have a ton of promotion otherwise.
Personally, I'll always have a soft spot for WRBB owing to my time there but really you can't go wrong with any of these.
Curious how you chose the default 8 stations? This is obviously super nitpicky but WERS deserves the Boston spot over WHRB IMO. Yeah, Emerson isn't exactly a powerhouse school, but their radio station is a legitimate player in a major radio market in a way that most college radio stations (Harvard's included) aren't. Definitely more important in Boston than WHRB is.
That aside, I'll two stations to your list: my former home station, WRBB, in lovely Boston, Massachusetts, and WMBR across the river in Cambridge.