And it still is, as many satisfied users will tell you.
Don't you like having tabs in your browser or windows in Vim? I remember the same argument being made when tabs were introduced in web browsers and yet, most people aren't complaining now.
But what Google is introducing seems to be similar to their Google Talk "windows" that are already available in Gmail. They come in two modes: Either I get a small Ajax-y popup on the bottom right of my browser window, which I cannot resize, move or see when Alt+Tabbing/Ctrl+Tabbing. I absolutely loathe this mode. The second mode is where they pop out an actual window. I like this mode, as I can interact with the chat window as with every other window on my desktop. My assessment above is based on this experience.