Help you convince your friends that you made the right choice?
I'd just tell him your reasons. He can agree or disagree, whatever.
It's a good choice for some, not for others. It depends what you want. I used to do a lot of productive work on my iPad, but now I only want to use it for reading and browsing since I have a very portable laptop. I find the iPad a bit heavy, but it was worth it for such a great device. Now that I don't need so much screen real estate and I won't type often, I'd rather have the smaller form factor. Some of alternative small tablets are very good. The Nexus 7 is very nice. But I prefer the idea of a slightly bigger screen on the mini and I prefer the App Store over the Play Store. I have good apps ready to go and I even have some credit to use in the store. The build quality is always superior on iPads too, so I'm assuming the iPad mini will be much the same.
If I wasn't such a big fan of the apps available on Apple devices, and I didn't mind the device being a little thicker and heavier, I'd definitely get a Nexus 7. For me, the exact specs aren't as important as how they come together to make a good user experience. I prefer using the iPad than Android tablets and I prefer the apps. That along with the size and weight of the mini makes it preferable for me. But I can see why others would prefer an alternative. Nobody is right or wrong here, we all have our reasons. If you're struggling to find a good reason to buy, then you probably shouldn't... but you did. So maybe you know exactly why you bought it, but can't find good reasons your friend will accept. Well **** him, he didn't pay for it. If he prefers higher specs on a smaller tablet he can go get a Nexus 7 with his money. Whatever.