fraternity ranks

The easy answer is:
Top: Sig Beta, SAE, and Sig Ep
Upper middle: Theta Chi and Lambda Chi
Mid: TKE and Sig Nu
Lower middle: ATO, Kappa Sig, and AGR
Low: A Sig, PMD, and Sigma Chi
The extended answer would be:
Top: All three houses I listed top have a reputation for having a decent group of attractive and athletic brothers. Sig Beta and SAE obviously have the biggest houses on campus so because of that they attract a very large pool of people to choose from, which allows them to be the most selective. Sig Beta is a local fraternity meaning that's the only Sig Beta chapter in America so because of that they have a very strong relationship with their alumni who give a lot of money back to the chapter that allows them to maintain their nice house. I've heard you can't rush Beta your first semester freshman year, however I could be wrong. SAE has more of the stereotypical "douchebag" reputation and were on probation this past year, however they should be off probation for this upcoming semester and allowed to throw down again so I'm sure they'll be very popular this upcoming year. Sig Ep has been a popular fraternity at UNH and was one of only three frats who threw down regularly last semester, however they are nationally going dry so I don't know how that will affect the future of the chapter or their ability to actually throw down at their house.
Top Middle: Theta and Lambda are pretty similar. Both fraternities actually have decent houses and there is a mixed bag of brothers in both fraternities. Some brothers are really attractive and outgoing and others are less so. They both threw parties very often, but Lambda definitely threw the most parties of any frat last year. Also a lot of Lambda's popular brothers are the young ones so that's a boost for them and Theta is losing their house in two years when PIKE takes it back so thats definitely a downside for their future.
Mid: Both frats have a decent group of brothers but TKE's biggest thing is they don't actually have a house to throw down in. They all rent out the Webster's on Madbury right next to Sig Nu. Sig Nu has fell to the wayside due to being on probation but they have a decent house so being off should help them out as well.
Low Middle: ATO and Kappa Sig don't have houses that their brothers collectively live at outside of small "satellite" houses and it's hard to ever be a super relevant or popular frat when you don't have a house to throw down in. Both fraternities have recently recolonized so maybe they'll eventually get houses and be more popular. AGR has a house but they are a relatively small fraternity and are known as the "hick" frat. They do throw down occasionally though and their basement is wicked nice.
Low: A Sig, Sig Chi and PMD all not only don't have houses but are also generally just not even known of. I feel like they tend to attract guys who couldn't get a bid anywhere else.
I hope this helps! Going Greek is really how you get the true college experience!

Fake news. TKE is number 1 and its not even close

Top: TKE
Upper middle: Sig Beta, SAE, and Sig Ep
Mid:Theta Chi, Lambda Chi and Sig Nu
Lower middle: ATO, Kappa Sig, and AGR
Low: A Sig, PMD, and Sigma Chi

Top: Beta- always has been, prob wont change for a while
Upper Middle: TKE- lodge is a great spot, rent the Webster’s tho so they could lose it at any time
Middle: Theta chi, lambda chi- theta is losing their house to pike and lambda is just in the middle in terms or parties and guys
Lower middle- A sig, AGR, ATO, Kappa Sig- these 4 seem to all be grouped together a lot, all below the other 4, but not the worst frats on campus, they are very mid
Upper lower- SAE, Kappa Sig, sig Chi, Pike- SAE and kappa sigma are off campus right now but the guys are cool, not having a house will always hurt you tho, and for sig chi I never hear much about them. Pike is getting thetas house so they are on the come up
Lower- Sig Nu, and any frat I missed- no explanation is really needed