I've never heard anyone describe the experience in less than glowing terms. When Al Gore took part in a keynote session at VoiceCon Orlando last March, his praise for the system was effusive (and unprompted).
The first and most obvious criticism of telepresence is its price: A quarter of a million dollars is about par for the course to equip a single room, and you obviously need at least 2 of them for the system to be useful. That doesn't count the 15 Mbps (for 3 screens) of flawlessly-performing bandwidth that you'll have to contract for. There's often a managed service involved, and the cost can near $20K a month for this connectivity and management.
Still, international travel is expensive and getting more so; building a business case around travel avoidance isn't a particularly steep climb for a multinational enterprise. The question with video is always whether it actually will pre-empt travel. Some analysts say the issue isn't travel avoidance anyhow; it's improved collaboration, especially with overseas offices and partners where relationship-building is inherently more challenging.
The main issues around telepresence right now seem to be:
1.) Interoperability 2.) Technology substitution
The issue around interoperability is that there basically isn't any; a Cisco telepresence room can't talk to an HP room, for example. This is a classic scaling issue--if a single enterprise has just a handful of telepresence rooms, there's no problem being a single-vendor network. But if telepresence becomes more common, and you want to talk to any partner or customer in any part of the world, some level of multivendor interoperability is going to be needed.
"Technology substitution" centers around what's been called "telepresence lite." Some enterprises have tried to put in high-definition videoconferencing without going the whole hog for the environmentals and design that vendors like Cisco say are essential for successful telepresence meetings. I've seen a range of opinions on whether this is an effective strategy or a half-measure that accomplishes little or nothing. Here are some resources at No Jitter where you can get more information on telepresence:
And an in-depth feature: