Oscar de la Renta suits come from a Dominican and Latin America background. He is a longtime legend in the clothing community.
Oscar has been a mainstay in fashion since 1965. He learned from the same school as Bill Blass and Calvin Klein. One interesting side note is that he added the "de la" as a way to make his label sound more prestigious! He is one of the premier Latino designers in the world.
His suits are worn more by celebrity women than men I'm afraid though. Still, they get some pretty hot names: Megan Fox, Penelope Cruz, and Gisele Bundchen.
For men, their suits seem to be pretty conservative. They do have some nice accessories that can be very colorful. Not great for the office, but if you want to add some flair their scarves and pocket squares had some zip to them. They also have a decent selection of men's blazers. From a quality standpoint, they are on par with a Bill Blass or Geoffrey Beene. They are basic, fused suits and are fine if you can get a decent one used or for under $200 or so.
Their mens wear is definitely very hard to find. Neiman Marcus does carry a wide array for women but not much for men. Saks Fifth Avenue have also carried them in the past. I've also heard that they made menswear under the Macy's house label, at least a couple years back, but I haven't been able to confirm this. eBay and Overstock are decent options as well.