FWIW, I have tower style PCs, an Android tablet and most recently an iPad 4.
The tower PC's I use mostly for work, intensive graphic work and messing around with large sound files. The combination of versatility with keyboard and mouse, large screen size, acres of storage and raw power means that is is very unlikely a tablet could replace these functions, ever. Who the heck would want a 24" tablet, for example.
The Android tablet, is much more open and free than the Apple alternative, easier to customise and generally works well. Google Play, the Android store, also has a huge number of apps, many free, and some of high quality. The Android tablet, a Sony, is also very light, despite being 9.7 inches.
The iPad, is elegance personified. It looks beautiful, with the Retina screen making a real difference, especially with reading e-books. Flawless in operation, and backed up with some seriously good apps. But, it is the Apple way or no way. Unless you want to jailbreak the tablet, which carries the risk of it not working any more. It's also expensive, and quite heavy by comparison to the same sized Android tablet, and not as easy to hold upright. Such as when reading in bed.
So, at the moment, it's the iPad that I tend to use for most recreational computing, and the tower PC for most work related stuff. But, the big deal for me, is that I detest Windows 8 so much - and have been very impressed with Apple - that my next PC (ifI can scrape together the money) is likely to be an iMac.