Definitely post this to the Kosher board as well - Having eaten at the Prime Grill in Beverly Hills when it was open - I would place Pat's as being comparable - Shilo's also is very but I like Pats just a bit better -
Other that I have heard good things about but have not been to: Bocca Steakhouse and La Gondola.
If you are willing for a drive in Oxnard is one of the top rated Kosher restaurants in the US Tierra Sur - it is in the Herzog Wine Cellars
9233 W Pico Blvd # 200, Los Angeles, CA
Tierra Sur Restaurant
3201 Camino Del Sol, Oxnard, CA 93030
9025 Wilshire Blvd Ste Frnt, Beverly Hills, CA 90211
16610 Ventura Blvd Ste 3, Encino, CA 91436
I'd suggest posting this query on the Kosher board: http://chowhound.chow.com/boards/28
With that said we have friends who swear by Shiloh's Steakhouse in WLA. Can't vouch for it personally as we have not been.
Shilo's Kosher Restaurant
8939 W Pico Blvd, Los Angeles, CA 90035