5) Well, I AM interested in unified communications. But OCS seems to lack features we need.
That's very well possible. Perhaps the most well publicized is OCS' lack of support for E911, which gives out a caller's physical location during an emergency 911 call.
VOIP systems, because of the multiple, complicated ways that data traffic can be routed, are not inherently able to do this as regular landlines do.
Although consumer VOIP services such as Vonage are required to offer E911, enterprise VOIP software is still largely exempt, though some IP PBX makers are offering it.
Microsoft is working on E911 and is deciding whether to introduce it in a Service Pack to OCS 2007 or wait until the next release, Akers said.
To get around the lack of E911, Lionbridge plans to maintain at least one non-VOIP line in each office for emergency calls as it phases out its PBXes, Kaldestad said.
OCS also lacks a fixed-mobile convergence feature that allows users of Wi-Fi-enabled cell phones to make free VOIP calls.
NEC plans to roll out this feature in its UniVerge mobile client by the end of the year, Lopez said.
"Do I really want to carry my laptop around to make a phone call?" he asked.
OCS also only integrates well with BlackBerries and Windows Mobile smart phones. Smart phones running the Symbian operating system make up 75 percent of the market, according to research firm Canalys. But Akers said Microsoft has no plans to extend presence support to them.
Another feature that OCS lacks, according to Kaldestad, is a virtual receptionist that can answer and direct incoming calls.
OCS also doesn't remove the need to maintain conventional fax lines, as Kaldestad found that employees still strongly prefer to fax hard copies of documents requiring signatures, for example.
"It's not a PBX replacement yet," he said.
6) Why go to OCS if we're not a Microsoft shop?
Wooing companies that are not heavily on the Microsoft stack will be one of the company's biggest challenges.
"If a company has already started to deploy unified communications, there is a very low chance" it will switch to Microsoft, Intellicom's Marks said.
There's plenty of competition for loyalty. For instance, telecom vendors such as Cisco have their adherents. For another, IBM is reinvigorating Sametime to convert its still-formidable base of Lotus Notes users -- and small but growing number of Symphony office software users.
Moreover, users need Exchange 2007 to take advantage of many features in OCS, Freedman said. But doing that "locks you into specific IT and telephony infrastructure, which doesn't make sense," Siemens' Straton said.
David Sengupta of Ferris Research expects OCS' uptake primarily among "Microsoft-centric organizations willing to put up with some growing pains over the coming year or two while Microsoft plays catch-up in this arena."
Marks also expects Microsoft to "work its huge base" of Microsoft Office and Exchange e-mail customers and grab some "low-hanging fruit" that way.
But even among diehard Microsoft shops, OCS won't be a no-brainer upgrade, according to Burton Group's Gotta.
"The deployment of OCS 2007 will be slower than expected within Microsoft shops because of other projects [Office SharePoint Server 2007] that sap IT resources and raise overall change management concerns," he said. A "critical mass" of customers won't start moving to OCS until the second half of 2008.