I had dinner at Chilango's the other night and had a good ceviche. I also got lunch at Blue Water Seafood and although I didn't have the ceviche there I saw some being served and it looked quite good. Btw, I would highly recommend both of these places. Although my meal at Chilango's wasn't as good as my last time there, the server could not have been friendlier and the food was all enjoyable, especially considering the prices.
I have seen some postings about Marsicos German and Godoy having good ceviche. Any other suggestions? It certainly doesn't have to be a mexican restaurant. Although I enjoyed the one at Chilangos, it only had one type of fish. I sometimes like the ones with a variety of seafood.