I've been to the new Oak Park location twice now, and came away happy both times. The new place looks spic and span, like an Asian version of Naf Naf in Niles. Almost chain like, but don't let that put you off.
Katy's Oak Park

Operationally, it's pretty much the same as the original Westmont location, just slicker looking. You place your order at the cashier in front, then sit down and wait for your food. They do give you a nifty number to put in a stand on the table so they know where to deliver your order, but that's the only operational difference at this location.
When Katy's took over the location there was an existing menu of pan-Asian favorites with Thai, Japanese and Chinese items. After sampling one of the items form the old menu, I'd say stay away from that in favor of the one page typed sheet of Katy's standards, which are executed as well as at the other locations.
I've now been able to try several of the Katy's standards.
Katy's Oak Park Xao Long Bao
These have arguably the best filling in the city, but are somewhat marred by slightly too thick wrappers. I still enjoyed them, though.
Katy's Stir Fried Onion Pacake W/Pork
This was every bit as good as the version served in Westmont. I suppose there might have been a slight deterioration of the noodles because they are made in Westmont and shipped to Oak Park, but that's only a small quibble and very well might just be my imagination.
Katy's Pickled Cabbage with Pork Belly Noodle Soup

This is one of the items they recently began offering in Westmont. Although I tried and loved the fish version of this soup, the pork belly version that I had in Oak Park was even better (to my taste). The broth was subtle, with a nice sour flavor thanks to the pickled cabbage and a pronounced backnote of ginger thanks to big chunks in the bowl. I highly recommend this soup on a cold day!
All in all, I'm ecstatic to have an outpost of Katy's closer to the city. I'm not sure it will completely replace Westmont as my preferred location, but at least I'll be able to visit Katy's more often. ATTENTION OAK PARKERS: They deliver, which makes me a very jealous guy.
Steve Z.
“Only the pure in heart can make a good soup.”
― Ludwig van Beethoven