I don’t necessarily think this is true. While Blackwater Inc. may not have tanks, Apache’s and A-10’s at their disposal, they don’t really need them. They are basically an Infantry fighting force, with weapons and tactics suitable to that goal. Long arms, pistols, sniper weapons platforms, light-heavy weapons, and some rotary wing aircraft are all in their arsenal. I believe, though I have no cite at the moment, that they also have purchased several armored vehicles for use in their current Iraq work.
As for training, many if not all of the operators that they and most of the other PMC’s use are almost always honorably discharged former military or law enforcement personel. The fact that they are there at all is a testament to the fact that they are capable of doing their job.
As for discipline… yes. I have heard first hand how some of the regular army guys don’t particularly care for the demeanor and beahavior of some contractors. However, as they are not subject to the UCMJ, they don’t feel a need to be as strict amongst themselves. It is not my place to say if that is good or bad, but it can be a factor in what and how the contractors are deployed.