I've been using them for 3 months now and:

1. They're more difficult to clip in, but once you've learned the technique it's not that bad.
2. You can leave your cleat covers at home because these are easy to walk around in.
3. The rubber on the cleats doesn't last too long - 2-3 months and they start peeling off, though of course this depends on how much you ride (or walk around after riding...)

So... I'd say I'm pretty indifferent - they have pros and cons. That said, the next pair I'll be buying will be non-grip if they're still available.