We have 2, and at first, a lot of the photographers hated it. Now, we're fighting over who gets it when there are multiple stories that could utilize it.
Pros: We can get live just about anywhere. We're in large metro area where cell service is hardly ever a problem and the dozen or so times I've used ours, we haven't had a single problem. It really gives you a tool to do things that were simply impossible a few years ago. We've done a lot of live shots while driving in cars, walking along with protest marches, inside buildings, things like that. And, it gives us the ability to have a live presence in places like downtown, where the tall buildings block any sort of microwave signal.
Cons: First and foremost, the backpack is heavy if you going to use it on your back. We've upgraded our software and are using full size XD cams with it now, and it feels like a ton of bricks after about 10 minutes. There's also the issue of the delay, ours was around 5 seconds, but with the software upgrade we've gotten that down to like 2 seconds, very similar to a satellite shot. And the quality of the picture isn't *great* but it's getting better.
One of the bigger issues that has nothing to do with the hardware itself, is that at least for us, the producers are beginning to push for more and more live shots from places or events that we could have never done before. It's a fine line, but they're beginning to expect things that just a year or so ago were impossible. All I'll say, they tend to forget what some of the things they ask entail from us, logistically, and physically. Walking along with a protest march is great, but when you get to the end, and you're 2 miles from where you parked and have to walk back, they don't think about things like that.
But, all things said, I love ours.