I have not been to the Peterson location in some time, but I can assure you that at its best it was never among the best in town, which ain't saying much for Cuban in Chicago.
As for Mi Ciudad, I really like the encocado dishes. This is seafood (fish or shrimp us.) in a coconut milk sauce. Similar to the Bahian dish moqueca. Other similar dishes are made en cacahuete (peanut sauce). If you like goat, the seco de chivo (reduced goat stew) is really very good. And for meat and potato diners, the steaks are (as it typical of S. American places) flavorful and inexpensive. While Ecuador says it invented ceviche, the Ecuadorian version is maybe my least favorite.
A great, varied cuisine, IMO, because it has the "cowboy" foods of Argentina, Colombia etc., some afro-carribean stuff like Brazil eg, and more exotic Andean stuff shared with Peru; even (like Argentina) an Italian influence. And the cooks are usually solid, since Ecuadorans are in every high-end kitchen in town. I've been told that the Mi Ciudad chef is on the lunch staff at one of the big steakhouses.
The space is (was) very pleasant. They had a fire but reopened recently. I have not been since the fire, but it looks to be even nicer from the outside.