Just returned from a two day stay in this hotel. I have a client with offices in both DC and Arlington, and this option is much cheaper than a central DC hotel. Central DC Marriotts can cost double the price of a room here.
It is a typical residence inn, getting a little bit tired looking in the rooms, but its clean and nice. The location is great - Starbucks across the street, close to the metro and a grocery store. That's good because every room has a full kitchen. The hotel will even go grocery shopping for you, but i didn't use it or do any cooking. The rooms are decent size and the bed is ok.
This hotel seems to cater to the High School field trip to DC crowd. Then i stayed it was full of grade to high school kids, but that was fine. it wasn't noisy.
The included breakfast and dinner is decent. Breakfast probably a little better. One night they had spaghetti and meatballs.... yes, that's what i said. Probably something to do with the school kid crowd. There are some local restaurants if you cant deal with the crowds or the food served.
I cant comment on the pet policy because i was on a business trip. What was important to me is that my room didn't smell like dog. I'm happy to say both my room and my coworkers rooms had no sign or smell of a pet staying there.