I had a Samsung Galaxy Tab for a week, and I thought it was crap. It's a little unwieldly, heavier than it should be, the form factor isn't so pretty (hard edges make extended use uncomfortable).
Also, the Android OS is ... in my opinion of course ... limited and RUBBISH.
Whilst I don't own an iPad myself, I've had an iPhone for over a year, and have used and configured iPads, and I'll tell you hands down that it is the easiest, most intuitive tablet there is,.
That's why iOS is the best mobile operating system out there, because it just works and you don't need to be a rocket scientist to perform the most complex of tasks,
To conclude - iPad. Every time. Unless.