Oh, oh, oh!
My friends and I been to countless Mexican seafood joints in the general area bordered by 7th and 28th and Van Buren to Thomas in search of a good solid place for ceviche, campenchana, cheap beers, etc. Mariscos Playa Hermosa is by far the best place we've been to. Once we discovered that place, our search came to an end and we haven't gone anywhere else since. It's our new Sunday afternoon spot! The place is clean, the furniture is really quite nice (carved and painted wood tables and chairs), and the staff is very friendly and attentive. 2 flavors of Mexican draft beer are offered for just 2 bucks for a large - one of them is Tecate, I don't recall the other one (might be Modelo though). A heavily loaded ceviche tostada runs 3 bucks. I've had the campenchana a few times and it's always been very good.
I've had the campenchana at San Carlos Bay and it was also good, but it's been upwards of 5 years since I've been there. I do remember the place lacking decor and decent furniture, but that may have changed. They place gets consistently good reviews on various online boards from others.
Mariscos Playa Hermosa
1605 E Garfield St, Phoenix, AZ 85006
San Carlos Bay Seafood Restaurant
1901 E McDowell Rd, Phoenix, AZ 85006