I'm working through a consulting company right now and it has been a great experience so far. The staff is professional, they don't micromanage and they can deal with my rates, about which they never complain.
I received a call the other day from another consulting company and if my initial read is correct, dealing with them would be lousy. The account manager called me and talked to me for 20 minutes straight about how tough the sell was going to be to the particular customer. The entire conversation on his part was obliquely related to the expectation of hourly rates and how mine were higher than what they were hoping for.
My reaction to this is always the same: "OK. So?" In other words, what's the problem? If the number is too high, find somebody else. Well there's the problem. It's hard to find an independent consultant specializing in this particular niche technology. You can always call the software company who owns the technology we're talking about—they have consultants, too. Here's the catch: they want to score over 200% of my rate for their consultants.
So it's all relative to the market just like every service for sale. Here's the bottom line question for third parties: are they willing to tell the end client the "bad news"? Because I never hesitate.
