Ok...I actually own a mini, a Nexus 7, an iPad 3, and a Nexus 10.
On movies....
Black bars: Those black bars are not a function of resolution. They are a function of the shape of the screen vs the shape of the movie frame. The mini has a squareish screen and the movie frame is wide. Thus, when the movie plays there are black bars on top and bottom. The retina iPad as more than 1080p resolution, yet you still see black bars on top and bottom. Now, here is what people seem to be forgetting...the mini screen is a good bit larger than the screen on the Nexus 7. In fact, the image you see on the mini -- even with the black bars on top/bottom -- is larger than the image you see on the Nexus 7. Also, the extra resolution on the nexus 7 doesn't come into play on a movie because the image is so small that you can't see it on a movie. The place were the resolution in a movie makes a difference is when the screen is large. Without the extra resolution, you would see the pixels on your tv. You'd need a magnifying glass to see the differences on a tablet. One has little reason to go above 720 -- if that, on a tablet.
On the iPads there is a zoom bottom so make the movie image fill the entire screen. if you use this button, you lose parts of the image. I don't recommend using it.
Now, if you want the best movie experience on a tablet, in terms of image size, get a 10-inch Android. Of my four tablets, the Nexus 10 has the largest image, then the iPad 3 comes next, then the mini, then the Nexus 7.
I do think the Nexus 7 is a competent e-book reader, but I have zero problems reading text in the mini. The one advantage of the 7 is you can hold it in one had vertically, like a narrow book. I can do this with my mini, but it is more comfortable on the Nexus 7. But with the exception of the nexus 7, I hold all of my tablets in landscape mode. The Nexus 10 feels unbalanced in portriat mode to me.
The battery life on my Nexus 7 and my Nexus 10 sucks compared to the iPad. And if you let the Nexii just sit unused, they drain down anyway. I'm not getting this at all. The iPad don't do this. BTW, the Kindles are the King of keeping a charge for long periods of nonuse.
As for the video...the guy doesn't even own a mini...I would take his words with grain of salt. He needs to use one to qualify this opinions. I don't even hold my iPad 3 vertically like he does. I get a more stable grip with the device in landscape mode. That vertical weight is unnatural, IMO.
I agree with him about how easy it is scratch an iPad, though, that cannot be denied. I have the black mini and I immediately put it in a case because the back will scratch. But he is wrong to suggest that the devices are not durable. They are very durable, but they still scratch. The iPad is a premium device with a premium feel. If you bang it around the finish will suffer. But if you buy a premium car it will get scratched up easily too if you don't protect the finish. That said, both of the Nexii feel better in the and than the larger iPad. Not so much so for the mini, but I don't like holding my iPad 3 naked in my hands. I don't like holding metal. I had the Asus Infinity Pad and it has a metal back and was the most horrible thing to hold. Its edges were sharp, even compared to the iPad 3. The Nexus 10 feels good, best of the iPad 3 and Infinity Pad. The mini feels better in the hand, but I keep mini in a case to protect the finish, because I might want to sell it when the new mini with a retina screen comes out.
Another reason to consider a case is to get a stand. I have all of my devices in cases has give me stands. My Nexus 7 is in a case that covers the back and gives me a way to prop it up. Same with the N10, iPad mini, and iPad 3. If all you plan to do is read & response to email, then you can forget the case. But what happens when you want to watch a video? A tablet in a case sits up anywhere.
On quad-core processors.....quad-core doesn't mean faster. Plenty of dual core processors are faster than qual core devices. And quad-core doesnt' say jack about whether it is improving the responsiveness of the device. I don't think most tablets even need quad-core processors...it's stated mostly for marketing purposes. I have some of the same games on iPad mini and the Nexus 7. The Nexus 7 doesn't seem any faster. In fact, in Beach Buggy Blitz, I think the mini is faster if you meausre it by smoothness.
They guy also made some comment about movie players playing anything on the Nexus 7. Not my experience. I had to download several players to get all my media to play. Same deal on iPad, though. If you want the ability to play more formats, get a player like AVPlayerHD or AcePlayer, or one of several others.
His comparison for the browsers was total nonsense in my opinion. Holdin the Nexus 7 upright on a webpage means you can't read any of it. Smaller screen means smaller text, too. I read webpages in landscape and I thus see more on the mini.
Don't know where in the world you are, but over in the US you get 14-days to return the device to Apple if you don't like it. I suggest you take advantage of it and decide what is best for you. Me, I like all the tablets for one reason or another....but I have to admit that for me, the overall experience is best on iPad. And that is mainly because of the richer content for tablets that Apple has made available. In comparison, Android is a wasteland. But I am an app guy...if you are not an app person, then this might be meaningless for you. To thine own self be true! You'll be happier that way.
ps...wrathchild is correct in the more colorful screen on the mini vs the nexus 7. The Nexus 10 is a bit better in this regard.