As an aside, is there much practical difference between brands?
Between brands to the normal user such as college girls in an apartment there isn't a lot of difference. Devices of similar prices will have similar features. A $150 Linksys will be similar to a $150 ASUS. A $150 Linksys will not be similar to a $300 ASUS.
What are some specs the girls should consider?
I could really geek out on you here and go crazy technical on ya. I'm really going to try to spare you that headache!
Given that they will be living in an apartment, I'd look for a dual band router (both 2.5ghz and 5.0ghz). The reason is that routers, like walkie-talkie's, have channels. If you're running the same channel as your neighbor, your network speeds will be much much slower. Having a dual band router, in an apartment with several other tenants gives them options. Options are good.
I would also look for this number that will be plastered boldly on the box and in any description of the router: 802.11ac
802.11n routers are great for a number of things, but for an apartment, with several devices (laptop, cell phone, tablet, tv, dvd player, roku, etc) the advantages of the 802.11ac are real-world throughput of 400 to 500 megabits per second (mbps) at close range; that's twice the speed of the best 802.11n routers. Told ya I could get geeky...
If you like, there are some simple security configurations that I'd highly suggest. They aren't uber secure, but they certainly help. I'd turn off the SSID broadcast so that when anyone else looks for a network to connect to, her's won't show on the list. I'd also enable DHCP routing. What that means is that instead of giving each device it's own permanent IP address, the router has a range of IP's that it assigns to each device. She turns on her laptop in the morning and her IP address could be 10.0.0.7. In the evening it could be 10.0.0.18. Finally, I'd enable MAC filtering. Basically, think of the best bar/club in town. The bouncer has a list of names of people to let in. Nobody else gets in. Her router can do that with MAC filtering. You set it up with the MAC address of every device she owns. No other devices can connect. That way nobody else piggy backs on her network for free, or other nefarious deeds.
Granted, somebody will come along and tell you that the above stuff really doesn't do much for security because hackers can spoof your MAC address, sniff your SSID, and spoof your IP address thus bypassing all of that.
They'd be right. This won't keep out talented and determined hackers. It will keep out that nosey neighbor kid in apartment 3b....
If you'd like help setting it up, PM me. If you're a DIY kinda guy then there are a ton of video's out there on YouTube that will explain exactly how to do that with which ever Router she decides to get...
Hope that helps a bit, Mike.
Good luck and congratulations to your daughter on her new apartment!