As with most answers; "it depends".
The iPad is designed to be "perfect". Straight out of the box you've got a great user experience. It's more responsive than other tablets, it's more intuitive and generally harder to "break". It's also quite expensive, but you pay for a prime piece of hardware.
My girlfriend has a Mac (Hackintosh, don't ask), a MacBook Pro and an iPad, and they work together like a charm. The whole ecosystem Apple has built is amazing. It all fits together perfectly, is extremely durable, pretty, and "easy to use", though somewhat limited.
I've got a Nexus tablet (the Nexus 7, the size of an iPad mini) and it's pretty much the opposite. Not that it's a crappy piece of hardware; it just takes a bit of time to get used to some of the user interface decisions they've made. Also, coming from an iPad (we have one at home, and one at work, that we build software for) it's just slightly less "perfect" on all fronts. The touch sensors seem slightly less responsive, the programs crash a bit more often, etc.
What you get in return, is a tablet that you can customize to bits. There are so many (free) apps, utilities, and settings in this thing.
More importantly, I don't have to use iTunes, which I loathe. I have an iPhone, but never update anything, and can't really put music on there because I don't have all the MP3's that are on that phone on my PC as well. So I'd lose half of my library. Stupid.
With my Nexus, I can hook it up to my PC and click & drag the files on there. Heck, I can even play movies over my home WiFi network. I download stuff on my PC and have access to it on the tablet whenever I want.
I also can download Super Nintendo games/emulators, hook a controller up to it and just play games wherever I want. And I believe I had to download support for flash, but at least it is available.
BUT, that's all stuff that you need to be a bit nerdy for. If you're tech-savvy not, go for an iPad. If you're a bit of a geek, I'd recommend the Nexus. I'm very enthusiastic about my Nexus, but the open-ness of the system is just not for everyone.
I won't touch on other tablets, because I don't have enough experience in day-to-day use of them, but they fall somewhere in between the two of these.
.ps: it was a fair bit of text so I highlighted what each part was about.
.pps: the Nexus also is a LOT cheaper than an iPad, if that factors into your decision!