We found call quality to be solid for a VoIP phone, and our overall impression was it seemed a hair better than that of the Philips VOIP8411B we tested, particularly in terms of loudness. Like your typical Skype call, you will get some clipping if your broadband connection--or the broadband connection of the person you're speaking to--is hit with any sort of congestion. In other words, unless you've got bandwidth to spare, you might want to ratchet down the World of Warcraft, Xbox Live, iTunes, or BitTorrent downloads while you're making a call.
Was quality any better compared with using a basic USB headset connected to your computer? Not to our ears. But that's not really the point. The real key is you can use the Linksys CIT400 just as you would a normal cordless phone. As you talk, you can walk from room to room and there's a built-in speakerphone on the handset if you want to go hands-free. That said, from a features standpoint, the Linksys CIT400 is geared more toward being a Skype phone, with most of its advanced features (call forwarding and voicemail, for example) designed for customers using Skype's optional services.
As a landline phone, the Linksys CIT400 is pretty basic. You do get support for caller ID (you can store Caller ID numbers in your Skype contacts list) and a flash button for call waiting. But you can't toggle between a Skype call and a standard call--taking one call disconnects the other. However, it's simple to put a caller on hold, mute the line, and then resume the call with a press of a button.
Linksys says you can get up to 12 hours of talk time and up to 120 hours of standby time from a fully charged handset (a pair of AAA 750 mAh NiMH rechargeable batteries are included). We didn't run any rigorous battery tests, but in one stretch we spoke on the phone for well over an hour and it barely put a dent in the battery life indicator. If you do end up leaving the handset off the dock for a few days, the battery will drain and doesn't seem to hold a charge like a cell phone can if you have it completely turned off. Of course, if you place the handset in the recharging cradle between calls, you'll be fine.
Like all cutting-edge technology, you can expect to experience a few quirks with the Linksys CIT400. Every once in a while, the phone will completely freeze up, and you'll have to pull out one of the batteries to restart it. (You have to hit the page button on the base station to link the handset to it again.) Also, when you add contacts to your Skype contact list on your PC, it doesn't immediately update on the phone and you may have to restart the phone for the new contacts to appear.
Another small note: setting the time on the phone is a two-step process. We set the handset's time to the local first, then went ahead and set the Greenwich Mean Time for our time zone (we checked on www.greenwichmeantime.com for the correct figure). For some reason the local time was thrown off after we set the Greenwich Mean Time, and we had to go back in to reset the local time to the correct time. But once everything was set correctly, our international Skype contacts' time zone information was accurate. We should also mention that the phone is firmware upgradeable, so there's a possibility Linksys will makes some tweaks as time passes. We're happy to report that there does appear to be some sort of auto upgrade feature, but since our firmware was deemed current out of the box, we couldn't test whether it worked or not.
Aside from its fairly basic design (some folks might think that's a bad thing), the biggest strike against the CIT400 is that Linksys doesn't sell any extra handsets at this time, so you can't expand the system beyond a single phone. (We've read reports that you can pair a Netgear handset with the Linksys base station, but even if that's true, it's a shame you have to go with a different brand to create a whole-house system.)
That issue aside, we really didn't have any serious complaints about the phone. It offers very similar features to the Netgear and Philips, it performed well, and you should be able to find it for less than those models, which makes it a good choice if you're trying to save a few bucks.