Ipads: Are they worth it?

The Hardware is not that different from the start, but if you want to change anything, Apple is the company that basically cuts off your hand if you try to.
Also, of course, the OS is very different.
The iPhone is very different than the Android. (It was even more different before Apple stole all of Androids greatest things)
Apple is "more stable" due to the lack of viruses, for the simple reason that the Macs contain very little valuable data.
(Not to mention, as far as quality and, as you mentioned customizability goes, Apple is far behind.)

 

Well they are stable due to some lack of malware yes, but that is mostly because it is less popular than PCs. If you are going to make malware you are going to try and hit the larger audience.

A lot of the stability comes from limited permissions and the lack of customability. If you are writing for an Apple product it is a lot easier to make it work on the devices because there are only a few setups that the end user could have. And with a lack of premissions it is far harder to write a code that will do any lasting damage, though by extension it is that much harder to do anything, including fix any error that does come up. As I like to put it, it is hard to break a Mac, but Macs break hard.