Here's an opposite perspective. I get plenty of value out of LinkedIn, both in personal and in business.
Personally, it's a great business card replacement. If I'm at networking events, conferences, etc. I also prefer to have my personal (Facebook) and business (LinkedIn) networks separate since I use them for very different purposes. On occasion, I've also leveraged groups to get specific advice I wasn't easily able to find elsewhere.
In running my company, LinkedIn also creates a quick talent pipeline and allows candidates to get a rough understanding of who will be interviewing them so we don't need to spend precious interview time answering their questions about our backgrounds.
I don't know of any replacements that do all of these things under one roof reasonable well. I do know of a few individual tools that offer incremental improvements over what LinkedIn offers, particularly in the area of finding qualified candidates, but in other areas (ex. digital business card) LinkedIn is the only real game in town.