For those not familiar with Bahia Kino (Kino Bay), it is a beach town about one hour west of Hermosillo. The highway from Hermosillo to Bahia Kino was recently paved and vastly improved.
There are two Kino sections, Kino Viejo, the old fishing village, and Kino Nuevo, the 5-mile "strip" along the beach of vacation homes and condos, mostly only 2-3 blocks deep from the beach. Kino has not yet been developed like Puerto Penasco with high rise condo resorts. It is a very quiet and calm place, except for the Mexican spring vacation time of "Semana Santa' (the Holy week period around Easter) when it can be quite crowded. It is a popular place for US retirees and vacationers in RVs.
Kino's beach is natural sand, while further south at San Carlos the natural beach is gravelly, and the sand is trucked in. It is very scenic.
A friend and I stayed at La Toninas Condos which are at the south end of Kino Nuevo and about 1/4 mile from the old town. The condos are on the beach in a 2-story building. While the furniture is not the latest fashion, we found the condo very comfortable and very clean. It had a full kitchen equipped with cooking and eating utensils. We had our own private balcony overlooking the sea and Alcatraz Island about a 1/2-mile out in the bay. The cost of the condo was $85/night which is very reasonable here where homes on the beach rent from $200 and up per night. The condo was air conditioned (rarely needed when we were there, but more necessary in the summer) and had high speed Internet access.
Another recent post about Bahia Kino mentioned a lack of ATMs and grocery stores. There was a small bank center in Kino Viejo with ATMs, ATMs at gas stations, and several small grocery stores. Kino Nuevo has 2 small "supers" and an OXXO (similar to Circle K and 7-Eleven).
There are many good restaurants, all offering local seafood. We especially liked Restaurant Marlyn in Kino Viejo and Jorge's at the north end of Kino Nuevo.
For those looking for ATVs to rent and jet-skis, this is not the place, though there are some available. It is more "laid back" and simple pleasant time at the beach. Fishing is available from the shore, in rented boats with or without guides, and from a new pier in Kino Viejo.
Sometime in the future, Kino will be on the new coastal highway being built from San Luis Colorado south of Yuma AZ to Guamas. The highway is not entirely desired by the locals, particularly by the native Seri people. It will eventually change the ambiance, though it is unlikely it will ever reach the level of development of Puerto Penasco. The highway is meeting obstacles from environmental groups which may delay its construction. Part of the coastal development is a string of marinas, La Escalera, being funded by the Mexican government along the Gulf of California coast. My favorite camping "resort" (it was very rudimentary, just camping spots, but it did have rest rooms and showers) on the beach at the north end of Kino Nuevo has been torn down for the new marina here. Right now it looks however that Kino will remain a fairly remote and private place. Some reviews of the studies done by agencies of the Mexican government have shown that they over-estimated the tourist interest in the coastal developments by as much as 400%. The construction is also fraught with corruption according to the reviews, and enriching the pockets of a few wealthy Mexican family groups.