Taken from : //www.macnn.com/reviews/leopard-review:-ichat.html
Leopard review: iChat
November 1st, 2007iChat wows users but still lacking in some areas
new layout, new benefits
iChat is one of the most obvious receipients of Apple's new interface design rules. This, more than most any program in Leopard, reaps the rewards: the lack of borders and the relatively utilitarian look mean more room for text, both in the buddy list and in any of the conversation windows.
The new interface also helps Apple implement several new features, some of which may not have been as easy to manage in Tiger. While not new to users of Adium and some other instant messaging tools, the option of tabbed chats proves to be a lifesaver when juggling multiple chats for users who prefer (or simply tend to use) the built-in software. Turning on this feature almost immediately reduces clutter, especially on MacBooks and other Macs where screen real estate is at a premium. The application's preferences also give far more in the way of condensing chats: a "compact" view shrinks the avatars and the text boxes to the point where several lines of dialog will fit where only a few would be available before.
A tabbed chat window with compact text
Version 4.0 also introduces a graceful way of keeping track of what is said in tabbed chats. In the tabbed view, text balloons appear next to users' names to indicate any unread messages, which disappear when the tab is acknowledged; every view shows the number of unread messages on the iChat icon located in the Dock. Group chats can even send an alert when a new user joins the conversation. The contact list can also be as organized alphabetically, or contacts can be re-ordered according the the user's preference. Favorites can be pushed to the top by using the group system from the AIM network.
iChat's main window with groups enabled
This new-found efficiency does create a few snags for users who may be used to certain window behaviors, however. In particular, I found starting a group chat to be less intuitive: rather than simply clicking an invite button to bring in the first new members, new group chats have to start by either typing names into a text box or dragging them to that location. Starting separate chats with individual members of that group after the fact is also less than natural. None of these issues are a major obstacle, but they could have been avoided.
improved connection support
Most of the application's intended user base may never see the use of these features, but iChat 4.0's new connection options may make it the first version to properly serve power users – those who are more likely to already be tied to Apple's preferred services.
Previously, iChat only allowed users to maintain one connection at a time with a given service. Leopard's edition of iChat is the first to allow multiple login sessions for the same service at once, with Bonjour as an exception. Although account choices are still limited to the AIM network, Google Talk, or Jabber -- Yahoo would be useful given the free mail account supplied with the iPhone -- this can be vital for users who need separate home and work accounts or who simply use more than one service often. I also appreciated the long-overdue ability to set oneself as invisible or to pick up a conversation through SMS texts if the AIM account is setup for mobile forwarding on AOL's end.
AV features and screen sharing provide mixed results, glitches
Apple's public demonstrations for iChat have centered around its video abilities. With only a few exceptions, most of these are not especially useful. I tried the backdrop and Photo Booth effects but found them interesting only in very specific circumstances, such as entertaining a younger chatter or omitting the background for privacy's sake in an office. The backdrops are also prone to creating problems, since Apple's method of keying the background and foreground assumes the background is static.
iChat's built-in backdrop effects (more can be added by the user)
Some owners of Apple's new aluminum iMac may also want to hold off on buying Leopard if they intend to use these features: in my few days of testing, activating the visual effects in iChat increased the likelihood that the system would suffer the chronic freezing issue or other glitches, such as turning the screen completely black or green. Apple has vowed to fix the general issue with updated video drivers for ATI Radeon HD video chipsets, but until then it may be safest to use conventional text or audio chats.
Despite this, iChat's advances should eventually be useful in Mac-dominated families and workplaces. There is not much that needs to be said about the iChat Theater presentation mode or Screen Sharing other than that they work well. As long as the connection between computers is quick enough and unobstructed, both function smoothly and leave little doubt as to how they can be controlled. Crucially, this is also the first iChat client that might serve as a basic podcasting client, since it can capture audio in AAC or video in MPEG-4. Editing in a tool such as GarageBand is still essential, but it no longer needs to be open during a live session. The only true problem with these upgrades is the same as with most of Apple's iChat features of years past: to make full use of them, both sides have to be using an up-to-date Mac.
Until now, iChat has always been the IM client experienced Mac users ran only out of necessity, such as having to conduct an AV chat or requiring a reliable file transfer method. Although Skype and Yahoo have caught up in some respects, iChat is still what most turn to when connection quality is more important than the luxuries of more robust clients.
iChat 4.0 does not entirely meet every need, especially for those who depend on Windows Live or Yahoo. Regardless, the improvements in day-to-day usefulness are hard to ignore when iChat is used regularly. iChat alone may not justify Leopard's $129 price-tag, but it could be enough to tip the balance in favor of a purchase for some fence-sitters. The additions may even provoke at least a few companies that turn to iChat for business purposes.
If these features sound appealing, then I recommend Leopard without much hesitation. The only users who should hold back are those who find themselves victims of unpolished video drivers or who only occasionally use iChat in the first place, particularly those who are not easily swayed by special effects.
Desktop and Finder
Minimalist interface. Tabbed chats increase efficiency. Intuitive. Cons
Still lacking some necessary features. Lack of Yahoo ID support baffling. Video filters can be picky.