How bad is the usage of the word suck in English? Is this "bad boy" language or commonly used?
It is certainly colloquial, and there are formal settings in which I wouldn't use it. Wiktionary marks it as "colloquial", and Merriam-Webster even as "slang". That being said, the word is not as "bad-boy" as many others, and is even acceptable in formal writing, depending on your audience. One famous example that immediately comes to mind is Roger Ebert's review of "Deuce Bigalow: European Gigolo":
[...] Rob Schneider [(director and leading actor)] took offense when Patrick Goldstein of the Los Angeles Times [wrote that the movie was] "sadly overlooked at Oscar time because apparently nobody had the foresight to invent a category for Best Running Penis Joke Delivered by a Third-Rate Comic." Schneider retaliated by attacking Goldstein [in an open letter]: "[...] Maybe you didn't win a Pulitzer Prize because they haven't invented a category for Best Third-Rate, Unfunny Pompous Reporter Who's Never Been Acknowledged by His Peers." [...] Schneider is correct, and Patrick Goldstein has not yet won a Pulitzer Prize. Therefore, Goldstein is not qualified to complain that Columbia financed "Deuce Bigalow: European Gigolo" [...] As chance would have it, I have won the Pulitzer Prize, and so I am qualified. Speaking in my official capacity as a Pulitzer Prize winner, Mr. Schneider, your movie sucks.
In fact, Mr. Ebert, an acclaimed and well-respected film critic with an impressive record, went on to publish an entire book titled "Your movie sucks".
In the 1980s and 90s "suck" was considered foul language and was used to create a shocking effect. As it has gotten to be more mainstream, it still retains an informal feel to it.
Now it depends on how you use it. It is much less offensive and kind of even friendly to greet bad news shared by a pal with "wow, that sucks", but still pretty mean to say "you suck." American Idol winner, Kelly Clarkson sings a cute love song that says "My life would suck without you."
Seth Stevenson wrote about suck back in 2006 in Slate: http://www.slate.com/id/2146866.
On a similar note, and just for amusement, here are some similar thoughts about pimp: http://evolvingenglish.blogspot.com/2006_06_01_archive.html