If you're a regular Skype user, you'll instantly notice the big facelift that version 4.0 of this voice-over-Internet-protocol service has undergone. It feels slicker and spruced up, and hopping from one feature to another is much easier. But the new version also seems a bit cluttered and bulky, and will gobble up more space on your desktop.

The new pane setup is responsible for the increased bulkiness. Skype 4.0 departs from its predecessor's two-window arrangement--one for your contacts, and one for your conversations--instead consolidating them into a single pane. Switching to the Compact View splits the pane in two, but the separated halves still felt bulky. Whether you keep the single pane or break it into pieces, more stuff is on display by default--and the panes are larger to accommodate all of it. For example, during a call, the interface displays a box with your photo (or icon) along with a message window and buttons for viewing your Skype account and personalization options. Though you can click to hide this box, I preferred the more discreet layout of past versions.

Some new features of Skype 4.0 work well. The new Conversations tab lets you manage a bunch of things at once, so you can flit around from video calls to voice calls to IM chats. And I like being able to engage in a video call right off the bat; with previous versions, you had to initiate a voice call on Skype and then launch the videoconferencing portion, provided that both parties had cameras up and running. Skype can handle a maximum of two talking heads during a given video call.

The company claims that audio and video quality have improved in Skype 4.0--and in my tests, I noticed that voices generally did sound slightly sharper than before. I never encountered words breaking up and sounding stuttered--something I experienced with previous versions of Skype. Indeed, the whole audio experience improved, including the moments of silence during test calls: Voices sounded as though they weren't coming out of a hollow, churchlike expanse of interior space.

The video quality of Skype 4.0 impressed me too. The video stream exhibited minimal choppiness, and I noticed just a couple of brief freeze-ups. Also, the colors appeared richer and less washed out.

With a VoIP program like Skype, improved voice and video quality trumps dubious interface changes any day. So I am moving to version 4.0. That said, some Skype users might want to skip this upgrade. If you use Skype's public chats, you should know that this version doesn't let you start new ones, though you can continue to participate in your existing chats. (Skype says that it plans to reintroduce public chats in future updates.) If you're content with the call quality of your current version of Skype, and you're happy with its look and feel, consider staying with the version you have. And of course there are competing services, such as ooVoo, to consider.