Riverside is a large city that encompasses over 15 zip codes, which include many upper middle class/wealthy enclaves such as Canyon Crest, Mission Grove, Hawarden Hills, Orangecrest, Hillcrest, Woodcrest, Alessandro Heights, and Victoria Country Club.
Riverside has many luxury car dealerships including Porsche, Audi, Mercedes, BMW, Infiniti, Lexus, Jaguar, Cadillac, etc. People in Riverside do most of their high-end shopping in Orange County or the desert luxury outlets, although there is a Nordstrom and Macys located in the city of Riverside.
Riverside often gets a bad image from some of the poor hoods and gang infested areas within the city.
The less fortunate residents of LA and Orange counties (ie. tools not living in Newport Coast, Beverly Hills, Coto de Caza, etc.), who try to ride on the coattails of their wealthy county's hype, often try to give Riverside a bad name to make up for their own miserable existence.
Truth is, Riverside is actually a very nice place to live. In Riverside, either you have it or you don't. Riverside is the epitome of "It ain't trickin if you got it," and Riverside definitely, "Got it."
(BTW, San Diego County happens to be the wealthiest county in SoCal, while San Bernardino is the least wealthiest)