Nexus 7 wasn't the first tablet to get people and companies alike to realize that budget tablets can work very well. I'd say the first one to start this trend towards cheaper tablets was the $99 HP Touchpad. Yes, it was a firesale, but a lot of people were trying to get one, even for $200 from other people, if it was sold out in stores.
Amazon was the first to notice this, and that's how the Kindle Fire appeared – a relatively decent $200 tablet, that wasn't a firesale, but it wasn't exactly profitable either. Then almost a year later, the Nexus 7 came out, Google's answer to the Kindle Fire. At the time Android tablets weren't very successful, so the Nexus 7 was both Google's way of making Android more popular on tablets, and to get developers to support the format, but also to stop Amazon from becoming very successful with a fork of Android.
I'd say they succeeded with both of their goals, as the Amazon Kindle Fire became a lot less popular since then, because people prefer to get the normal version of Android, that will get many OS updates, and costs just as much, and of course has many more apps thanks to the Play Store.
This year's Nexus 7 makes the gap between it and any other small budget tablet, including the Apple iPad Mini, even bigger. It has a much better display with a high 1920×1200 resolution and 323 PPI, it has a fast quad core processor, even if it's not the latest, and it has a great price of $229 for the 16 GB version.
You may want this tablet even if you're an Apple customer. The new iPad Mini may or may not arrive this year, but most leaks point to it not having a "retina" display anyway. It's also rumored to use only an A6 processor, which is the same processor inside the latest iPhone, and has a GPU twice as weak as the A6X GPU, that's inside the latest big iPad. That GPU was about as fast as the Adreno 320 GPU, so it should have around the same graphics performance, while the Nexus 7 may beat it in CPU performance, thanks to its quad core processor. Plus, the iPad Mini will still be $100 more expensive.
We've come to a time where Google and its partner OEM's make better devices than Apple, and not just in terms of specs, but also in terms of quality, while offering them for lower prices than Apple. It's very unlikely any other budget tablet will offer a better value than Nexus 7 this year, even if it has slightly better specs. Google's 1 million app ecosystem, stock Android, and fast upgrades to the latest version of Android make Nexus 7 a very compelling product.