Pros: Easy to integrate into SIP [freepbx] phone system. Really like the five "line" buttons, I set them up as BLF's, which works great! Voice quality on speaker and handset is excellent. Uses PoE, which reduces desk clutter by eliminating power cords and power bricks. Also, simple firmware updates, via web browser (no need for TFTP server)...

Cons: None worth mentioning in my opinion

Other Thoughts: I would definitely recommend this phone to anyone using an asterisk-based phone system. A few things that would make this phone better: lose the USB port and wifi and add three more line buttons. I now have three phones on my phone system: the spa508g, the spa525g2, and the old cisco 7960 phones. I LOVE the 7960's, but they are hard to configure with the proper SIP firmware and lack BLF functionality.

Pros: Works with Cisco Phone Systems

Cons: None

Pros: The phone has a wonderful display, and everything my customers love about the SPA5xx line. They look good, sound good, and perform well.

I have two of these units specifically for the built in WiFi functionality. Semi portable phones where my wired network doesn't reach. I find this to be a more secure solution than to use the other phones with the cisco wifi dongle (which can easily be plugged into any other device). The phone also locks out it's PC LAN port when on WiFi so nobody can try to plug into that.

Cons: The provisioning interface (web gui), while adequate, looks absolutely nothing like the rest of the phone's series. It's OK, but different. I don't understand why you'd make a whole series of phones, then change that on ONE of them.

Using Ubiquity access points with "zero hand-off" enabled makes these phones not connect to the network at all. They'll scan, see the network, try to connect, and get stuck there.
The phones are also only wireless G devices. Not a huge problem, but as ubiquitous as N is getting, you'd thing a $300+ voip phone would have it.

Custom pictures on the display and the ability to play MP3s off a USB stick hardly make this worth the premium it commands.

Other Thoughts: Awesome phones that work great with Asterisk. I just wish they'd left some of the fluff off. If there were a SPA504G with the wifi functionality built in (not the dongle) then I'd go for that in a heartbeat.

Pros: Most important, the phone has excellent sound quality for the handset, speakerphone, and Bluetooth headset. The buttons and unit feel sturdy and are perfect to the touch.

This phone has an amazing ability to use both a Bluetooth headset and also function as a Bluetooth headset to a cell phone.

Bluetooth range and sound quality is at least as good as on my cell phone and possibly better, especially the range.

It also some features that seem weird to me in a desk phone, like the ability to download MP3 files from a USB stick and play them.

The menu navigation is improved over prior SPA phones, with the addition of a physical select button in the middle of the direction buttons in addition to the selection buttons around the screen.

The display is genuinely useful, showing different icons and messages to help use all of its features.

The phone has a solid Web interface for remote administration. I found this usually (but not always) easier than using the menus on the phone.

Cons: Bluetooth glitch (depending on your preference): if you connect a cell phone to the SPA-525G2 via Bluetooth, and if your cell phone is set to send notifications to the headset, then when the cell phone sends those notifications, the SPA-525G2 will place your existing call on hold to give you the notification. This is a horrible thing to do. Better would be to just play the notification in your ear overlaying the call, or at least just mute the voice of the current call to play the notification. Putting the caller on hold is disconcerting and requires manually bringing them back from hold. I solved this by turning off Bluetooth notifications on my cell.

Also, through the web admin console, there are 2 view options that change what you can access, but it was not at all clear what settings require them. They are worded simply "Advanced" and "Admin". Neither of these appear to be necessary for most settings, though Advanced may have been needed for some of the Bluetooth settings. I found that I would just always turn both on, but this may well be exposing several options that I should not change. Better would be if it explained what these options enabled, either next to the fields when they're visible or in an online Help page. As far as I can tell, the SPA-525G2 does neither.

Other Thoughts: I use the phone as a RingCentral phone. Overall I love the phone. I was surprised how much the high-resolution color display truly helps with usage. Even when it's just displaying text, like missed calls, it's easier to read and just a pleasure to use.

I reserve 5 eggs for a perfect product and this has the problems noted above with Bluetooth and the confusion in the web interface. Neither of these are likely to affect most users, and even if they do, they are far from serious problems, unless you need to have Bluetooth alerts and intended to use the SPA-525G2 with your cell phone. In that case, this could be a fatal flaw.