The conclusion on the IG report?

Well your conclusion will be based on whether or not you actually take the time to read the 500 page report, or if you simply accept the increasingly embarassing conclusion that there was no sign that "bias" played a part in the Hillary email investigation.

The report clearly shows:

• Five FBI agents have been referred for some form of discipline, all having to do with anti-Trump bias.
• Key FBI investigators in the Clinton email probe had strong ties to the Clintons, but refused to recuse themselves. Others who did recuse themselves, because of Clinton ties, were still active in the investigation in spite of their recusal.  
• Absolute evidence that FBI agents were openly scheming as to how best they could resist the Trump Presidency, including slow walking or avoiding Trump directives.
• FBI attorneys were in on the act, including the increasingly viral term “Hell no. Viva le resistance” from an attorney originally assigned to, but later removed from, the Mueller probe.
• Multiple agents were transferred from particular duties based on evidence of anti-Trump bias.
• That key agents involved were openly hoping that the Russian investigation would bring down the Trump Presidency.
• Dozens of agents (including Sr Level agents) leaked sensitive anti-Trump information to the media. Many agents socialized with liberal media members against FBI policy. 

What it boils down to is that there was a widespread admittance from members of the FBI that they were open Clinton supporters, that they loathed Trump, that they hated the fact that they would be working for him, and that there was an open attempt to use their investigation powers to bring him down. They were caught red handed, making all sorts of suggestions that they wanted Hillary to win, that they took into consideration how their work would affect the election, that they would resist a Trump Presidency should he win (including using investigatory powers), but we are supposed to believe that this in no way effected their work as agents. 

Regardless of what side of the political aisle you are on... the idea that such partisanship and political gamesmanship is even being suggested (even mockingly) by so many different members of the FBI, should send a chill down your spine. The fact that agents openly suggested that they were investigating the President under the hope that they could bring him down is clearly a violation of every law enforcement norm we have. 

Anyone who would be still willing (at this point) to defend the actions of the FBI should reevaluate their ability to see things clearly. There is another IG report due out on the actual investigation into Donald Trump. Based on what we have seen in this report, it will be much more damning than what we have so far. Unfortunately, it may not come out before the end of the Mueller probe. If it comes out well after the fact, that is how it will be seen (as well after the fact). That being said, I would fully expect that the Mueller probe will want to wrap itself up "prior" to the IG report, which actually does provide a more tangible (if still artificial) deadline. No way does Mueller want an IG report coming out in the middle of his investigation, and no way will anyone accept that the IG report just has to wait till the probe is over.

Note: Horowitz is scheduled to appear before a joint congressional investigation to testify. I am sure he will face many many questions about how he can present 500 pages of factual evidence showing clear pro-Clinton anti-Trump bias, clear violations of regulations and protocol dealing specifically with this bias, many poor decisions that seems specific to this bias, but still made a determination that the admitted bias did not effect anyone's work.