You can't always tell with OVAs because they could be delivering something the main series does not (they're intended to appeal to the fans as an actual purchase, so they usually offer something different to the regular show, which could be "more boobs" in some cases, or excessive fanservice for a show which didn't actually have that much of that).
... continuing my comparison of Japan vs America's taste in manga, here's the most recent sales charts:
http://myanimelist.net/news/41240245http://myanimelist.net/news/41180547The Top three in America were Tokyo Ghoul, No Game No Life, and Akame Ga Kill. 2/3 of those are total boobfest harems, and all three were adapted into equally shit animes, plagued with terrible writing.
In comparison, the top 3 in Japan were Kimi ni Todoke, Uchuu Kyodai, and Kingdom. All well regarded series with excellent writing, and excellent anime adaptations.
Although if you look at light novel sales, everything flips around. The top selling light novels are all the dreck, and the majority are cheaply written novels that are aimed at 14 year old boys, basically they can have more "sexy" content but unlike a comic you won't get busted reading it. Since they're aimed at middle school kids, these sorts of light novels can get away with constantly repeating the same material in a way that wouldn't fly with older readers: 95% of the books are about some highschool kid who gets a demon power in his right eye/right hand, teams up with some magical/space/devil girls and battles against an evil conspiracy, in between hanging with his girls for funrtimes. Not needing artists actually makes a lower barrier to entry into the light novel market.
So, you have this odd situation in Japan where comic books are the bastion of good taste, and the real dreck is the print literature.