I recently read through them on my kindle in a flurry of nostalgia. I was surprised you could only get them through Pottermore, and they were more expensive than most kindle books, but I grabbed the set anyway.

It was an interesting experience and I found myself swept up in the same enthusiasm I felt when I was first reading them (I think I read everything from Book 3 upwards as they came out, the wait between them was excruciating). I've read many, better-quality books since then and while I found a lot of weaknesses I had never noticed before, the enjoyment far outweighed those weaknesses.