We have the Panasonic KX-TG5571M, not the KX-TG5576M. It's essentially the same, with the exception that you don't have the full color display on the phone and you can't synch it you your pc (why would you need it anyhow? unless you were using it for business applications). These phones do a great job and have no inerference at all, even with a wireless network running in my house. They also have built-in speakerphones on the additional cordless, that's a nice feature. They have selectable rings, and even different lights in the antennas, so you can tell one phone from the other.
The only quirks I've noticed on these are that when a caller from your address book calls you, it displays the name as it appears on the caller id (including area code settings and sometimes it even puts a 1 in fron t of the number even if its a local area code), not the name you programmed in the address book. the second thing (an this is not a big deal), is that when youy redial a number, the dialing proces is not very quick. The phone dials the number and it's kinda slow in my opinion. Aside from those two litle things, the phones are, as they say, "of da chain"
We tried the Motorola phones and, pardon my french, they sucked big time. I couldn't use the corldess piece further than 3 feet away from the base! I think this phone has a lot of nice features but its quality of range is not really good.
Haven't tried the Uniden or the AT&T, simply because I didn't like the way they looked. In my opinion the Panasonics looked better and the antennas were tiny. When our roomate moved out, she took her 2 corldless phones and that kinda lefts us in a bind.
All the reviews I've found are so old, the ones here are September 2004. Most of those models are no longer being sold. 
We want an expandable cordless 5.8Ghz system, capable of at least 4 handsets, with digital answering machine and speakerphone capability. We don't really care about Caller ID, we don't have that feature now. We don't really care about downloading little color pictures and custom ringtones. Just want a clear, good quality, reliable, useable phone that won't interfere with our other wireless gadgets. Anyone bought one recently that they like? Dislike? There must be a thousand different Panasonic models (so confusing!!), are they a good brand? How about Uniden? Motorola? AT&T?
Right now I'm still using my old old AT&T 9600 phone from the early 1990s because my newer 900MHz Uniden phone sucks. It interferes with the wireless network and has always had an echo in it. It has always cut out for no apparent reason when you tilt it a certain way too, like something's loose inside it.
We kind of liked this model at Best Buy:
Panasonic KX-TG5576M. Any yea's or nay's? Its the most expensive one, and has a lot of stuff we probably won't use.
Also Sam's Club has this one:
AT&T E5634B comes with 4 handsets, seemed to be an incredible deal for only $150.
What about the Motorola MD761? That looks like the same one that comes with Vonage VoIP service. Anyone love it? Hate it?
And everyone seems to sell the Uniden CLX485, but my previous Uniden has not been good, so its starting the race in last place.
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