I liked James Gunn's "The Listeners" quite a bit; I thought Sagan's "Contact" was essentially lifted from it, with a few bolder ideas thrown in. Neither novel impressed me that much; the aliens were simply too _human_. Or at least their motivations were. (Norman Spinrad's "Songs from the Stars" is a much better treatment of the SETI theme, in my opinion.)
Perhaps the best "first contact" novel I've read is Whitley Strieber's "Majestic," a fictionalized account of the alleged Roswell crash. You don't have to have an opinion one way or the other to enjoy this...I read it as a kind of spooky, well-realized alternate history. But the aliens in it--or, at least, their insinuated presence--is what makes this one work. They're genuinely "other," not high-tech versions of ourselves, which is a common pitfall in mainstream SF.