It is about time
It is about time. We almost had legislation similar this in Canada, but with our current minority government, the Liberals and the NDP prevented the Conservatives passing it. The Liberals and NDP didn't think computer crimes caused enough damage to justify creating new laws.
Keep in mind that there were already US laws against invading US government computers. So my understanding is that this bill's primary effect is to protect the protection of criminal law to privately owned computers.
A "felony" is a serious crime. With most crimes there is a line arbitrarily drawn between a misdemeanor and a felony. For theft, in some jurisdictions theft over $1,000 is a felony, in others the line is $10,000. The 10 computers is that arbitrary line that the authors of the legislation picked.
If someone is installing spyware and also stalking, then they are committing two crimes. Nothing in this new law would prevent prosecution for that other crime.
As for who gets investigated, it will be probably be those who commit the most serious criminal acts, as well as those who commit criminal acts against those with loud voices and good connections. FBI computers, as US government computers, were already protected under US law.