Just got my new MacBook in the mail a couple days ago. Last night I Skyped with my friend to test out the quality of the webcam. He was directly comparing the 480p webcam on my new MacBook with a 720p Logitech webcam that I use with my MacMini.
Seems that the webcam will get you by just fine when it comes to casual video conferencing. Most of the critics are underestimating the quality of the webcam just because of it's lower resolution (generally seen as abysmal for a 2015 piece of technology). However, the light exposure, coloring and frame rate seem to match the 720p "FaceTime HD" cameras Apple has in their other products. The only difference you might notice is a small dip in finer detail, and that's solely based on the lower resolution factor. Apple appears to be squeezing the best image out of this camera that they can get. Remember that this is only an issue because the panel of the MacBook display is so thin that it cannot house a FaceTime HD camera at this point.
DetroitBORG on YouTube has the best review on the new MacBook that I've seen to date. I highly recommend watching the entire review, but you may click this link to skip to the part where he'll show you real footage comparing the MacBook's 480p FaceTime camera with a MacBook Pro's FaceTime HD camera:
https://youtu.be/xRGxC9_I1K4?t=14m48s
In my personal opinion, the webcam in the new MacBook looks way better than I thought it would. My friend over Skype said the same, and noted how he couldn't tell that much of a difference over Skype. Now I should also mention that sound quality doesn't seem to be an issue either, and noise cancellation works great. Before purchasing, the quality of the webcam was one of two of my main concerns with the machine, with the other being performance. Luckily, both of these have turned out to be negotiable based on my harsh testing of the new MacBooks in the Apple Store and my experience so far with my machine.
You mentioned in your post that you're looking to use your new MacBook
mostly for video conferencing. I have to note that this will affect battery life and performance. This will also depend a lot on the service that you are using. I'd be safe to assume FaceTime is the best option when it comes to siphoning battery and performance, and that Microsoft's Skype and Google Hangouts are going to have worse results and affects on the system.
Before I began Skyping with my friend, I had unplugged my MacBook and it was fully charged. The battery icon up on the task bar gives estimates on remaining battery life depending on your current usage. Before my Skype session, remaining battery estimates were about nine or so hours. A few minutes into my Skype call, and the estimation dropped to just under five hours remaining. Also during the Skype call I attempted to multitask in other apps, with most of them running full-screen. So I was swiping between desktops and whatnot. This was all possible, but I did notice just a tiny bit of hit on performance, but certainly nothing big. However, we did experience a hitch in image quality in the call while I was doing this, but that probably has more to do with connection issues from either end of the line.
TL;DR: The new MacBook's webcam is actually pretty good, just keep in mind that video conferencing will almost halve your battery life and performance might drop a little depending on how much you have going on. I wouldn't recommend video conferencing on this machine all the time, but you can absolutely do it when you need to. This computer handles most of it just fine.