Bart Ehrman is a respected New Testament scholar, known especially for his work in textual criticism and the text of the New Testatment. This is his lecture series on the making of the canon of the New Testament, though I'd argue that he focuses more on the writing, theological, and authorship issues of the books of the New Testament, spending only the last couple of lectures on how they came to be included in the canon.
Throughout these lectures, I found that Ehrman had an ax to grind with Christianity, at least modern protestant Christianity (and especially fundamentalism), which is his background. Perhaps my prior view of Ehrman colored how I heard him in these lectures, but there were certainly blatant times where he was condescending towards Christian beliefs, more so than is necessary from the evidence of the making of scripture.
I think Ehrman often overstates his case and positions on the New Testament and how it came to be. He often appeals to scholarly consensus, which is not as unanimous as he implies. That being said, it is important to know the consensus and all sides of the debate and to know the evidence to inform our conclusions (this is the reason I chose to listen to these lectures). And there was valuable information in these lectures. However, if you are not familiar with these debates, you might take some of the assertions that Ehrman makes as settled fact when there is nuance and debate of these conclusions (a good book that addresses some of Ehrman's assertions is "The Case for Jesus" by Brant Pitre).
For example, one of Ehrman's famous (or infamous) analogies is to use the game of telephone to describe the oral culture and method by which Jesus' teachings were passed on before being written down, implying that they grew wildly inaccurate as they got passed down. However, modern word on oral cultures has shown this is not the case, and that oral traditions, especially those that are of historical events, have quite high fidelity. The model that Ehrman uses is representative more of the higher critics in the 19th and 20th centuries than today. Further, Ehrman emphasizes that the New Testament took "many years" and even centuries to come to be recognized in the canon, but this needs to be much more nuanced. It is true that there were centuries of decisions on the overall canon, but most of the canon was recognized by most of the church from a very early date, with only the fringe being debated.
Ehrman also makes a pretty big deal over the many different gospels and writings that did not make it into the canon, but I think he too overstates the cases here. If it were true that many different gospels were circulating at an early date in competition with the four that eventually got canonized, then the heretics would more often cite their own gospels. This doesn't start happening until the late second and third centuries (with the gnostics). In the early battles, heretical groups such as the Marcionites and Ebonites did not quote from other gospels, but rather emphasized certain gospels or rejected certain gospels altogether. For example, Marcion took for his scriptures a mutilated version of the Gospel of Luke, and the letters of Paul (excluding the pastoral epistles). Instead of quoting from variant gospel traditions, he modified the know traditions. This implies something quite different than 'there were various gospels all competing from an early date to get into the canon.'
Further, I don't buy Ehrman's model of the conflict between those who would win ('orthodoxy') and those who would lose ('heresy'). The canon was eventually formed by usage in the universal church, as is noted by several early authors when they discuss disputed books "that are not read/accepted in all the churches". If there were truly a group of people who forced the issue on all the church, then they did a bad job by highlighting disputed books and not forcing a canon early on. It is true that the early church used the theology of the books as one of the criteria of authenticity, but Ehrman makes this seem to be a bad thing as if you couldn't judge whether a book was authentic by whether or not it agreed with what was known to be the claimed author's belief. It is ironic, in a sense, that it is this very criterion that Ehrman uses to claim that Paul was not the author of certain epistles, such as II Thessolonians- because it supposedly disagrees theologically with what Paul writes in I Thessalonians. So, it seems that Ehrman can do this without bad intentions, but the early church fathers can't.
Overall, it is clear that Ehrman has a particular view of the New Testament that I believe is shaped by his context and background. This is not the material that I would suggest as a starting place to study the canon, though if you are familiar with the discussion it could be a good resource to hear a different perspective. There are good things you can learn from this (I particularly enjoyed Ehrman's walk through some of the gnostic writings), but it does come with a certain tone that I would say is at least a bit antagonistic towards faith.