As the developer of Phone Amego, I've had the opportunity to use several SIP phones in order to support them in Phone Amego. Ironically, many advanced phones are not very good at CTI, so I'd like to describe some of my own experience here. For home use, a VoIP telephone adaptor and cordless phone may be all that's needed. For professional or office use, SIP phones offer better sound and advanced features to make handling calls easier and more efficient.

Any phone call that passes through the PSTN (Public Switched Telephone Network) or an analog phone is limited to narrowband 4 KHz audio. To take full advantage of the Internet phone revolution, a dedicated SIP phone or soft-phone with HD voice is desirable. Many SIP phones include advanced speaker phones with built-in echo cancellation and noise reduction. The result is more like sitting in the same room as the person you are talking to (even if its a conference call with several participants).

In my experience, the leading SIP phone makers for SOHO users are Polycom, Yealink, Aastra, Snom, Grandstream, and Cisco. Each have strengths, but my favorites so far are Polycom and Yealink. Notice your ITSP (Internet Telephone Service Provider) may support some phones and not others, so that's a possible consideration.

Polycom has a well established reputation for the best sound quality, especially for multi-party conference calls. Their compatibility with VoIP services and support for CTI is excellent (probably the most widely supported phone available). Any of the Polycom Soundpoint IP or VVX phones should work well with Phone Amego. I was pleasantly surprised by the quality of the speakerphone on my Polycom VVX300. It sounds great and callers can hear me easily. These are terrific phones, but more expensive as you get into models with larger displays and more keys.

Yealink is a rising star offering advanced features (HD Voice, IPv6, and intuitive UI) at entry level prices. The user interface is clean and way ahead of most. The SIP-T22P makes a very nice office phone and is available for around $80. Support for CTI is simple and straight forward. Yealink phones are my favorite for value and ease-of-use. The display on the SIP-T20P is too limiting so it's worth the extra $20 to get the SIP-T22P or higher. As a relative newcomer, Yealink phones are not as widely supported but easy to manage yourself and growing in popularity.

Cisco makes many phones, but the SPA-xxx series work similarly to their VoIP telephone adapters which are compatible with Phone Amego. Cisco phones are feature rich, but not the easiest to configure or use. The hardware is solid, but the documentation is weak. How to install firmware upgrades from a Mac is not obvious (but possible). Any parameter change requires resetting the phone. My test unit locked up when pushed with invalid remote commands.

Aastra phones (67xx series) are often cited as one of the best phones for Asterisk with powerful multi-line support and application features. My personal experience is limited to the Aastra 9133i which does not support dialing directly. A somewhat awkward feature is that once you specify a notification URL to work with a computer for CTI, the phone will complain with a "Page Load Error" if the computer is turned off or not available. Lots to like, but not my favorite for CTI.

Snom phones work well with Phone Amego but the entry level models have limited displays. I haven't fully explored their strong support for open standards including uaCSTA (user agent CSTA - an industry standard for CTI). Sound quality is good. The Web UI and on-line support is better than most.

Grandstream phones offer great value, but limited support for CTI (no explicit notification for call events). Phone Amego works with the Grandstream GXP2100 by using the syslog feature. Phone Amego can dial the GXV3240 (Android based phone), but cannot detect caller ID since this information is not currently provided in the syslog. I like the Grandstream phones I’ve tried, but they are missing obvious application features that pretty much everyone else has. The company is headquartered nearby in Boston but so far they haven’t shown much interest in my suggestions.

Avaya phones are popular in corporate call centers and can trace their heritage back to Lucent Technologies and the old Bell Labs. With a large portfolio of proprietary phone systems, I'm not familiar with how they work in an open standards environment (SIP based VoIP).

Allworx phones are proprietary telephone instruments managed from a central server.

Other brands include Panasonic, and Siemens (Gigaset). I haven’t used these yet. If there's a great SIP phone I've overlooked, or you have other experience to share, I welcome your comments.

Q: I am really not seeing a lot of value in all this telephony hardware, since if software can be used for the same thing, I already have the devices, iPhones, iPad, Mac, PC, Apple TV, etc.

A: I used to feel the same way. The devices we have are really good and more than capable of acting as a phone with the right software. Why spend more time and money on dedicated telephone hardware?  It's a good question.

The other side is of this argument is that all modern phones are software. Why do you care what hardware the software runs on? What matters is the user experience. In my role, users kept asking me to add support for Polycom IP phones, so I bought one on eBay to try it. I was stunned at how good it sounds. Way better than any soft phone I've used. How is that possible?

Dedicated DSP hardware that has been carefully tweaked to optimize voice quality and clarity along with careful attention to audio system design in the handset and speaker. The result is a phone that sounds and works better, plus you get powerful CTI features built-in. In contrast, soft-phones are often poor at CTI.

By using a dedicated business phone, you gain stability (from upgrades and other ill behaved software), reliability, better sound, a better user experience, lower cost (cell phone plans are expensive), fewer dropped calls, better CTI, and business features like call transfer, hold, conference, mute and so forth.

Softphones and video conferencing on mobile devices are clearly going to be huge, but they are not a full replacement for a business phone.