In Act I Scene I, Romeo tells Benvolio his view of love:
Love is a smoke raised with the fume of sighs;
Being purged, a fire sparkling in lovers' eyes;
Being vex'd a sea nourish'd with lovers' tears:
What is it else? a madness most discreet,
A choking gall and a preserving sweet.
Love, then, is a roller coaster ride and a paradox. He sighs with longing and when he's tired of pining, his lover suddenly wants him again. Love is a stormy sea where his lover contributes rain. At the same time, love is both a "choking gall"--something he cannot swallow for its bitterness--and a "preserving sweet."
In Scene IV, he tells Mercutio, who is trying to make him lighten up--that love is a "heavy burden" (Mercutio disagrees), and adds that love is not tender at all. Instead, "it is too rough, / Too rude, too boisterous, and it pricks like thorn." The side of love he is experiencing at this moment is certainly not tender; he has been rejected by the object of his affections and sees only the painful side. Of course, when he spots Juliet, he rejects the notion that he was ever in love before, but surely this is true love (unlikely, as he hasn't even met her yet). He seems rather fickle.
Ultimately, however, his opinion of love is that, with all its thorns and storms, it is the only thing worth living for. When he believes his Juliet dead, he goes to her tomb and poisons himself, unwilling to live without her.