I had the 8700c and I can see how one might find the 8703e as 'less sturdy'. It's really just the small curves on the back and bottom of the 8703e. I can't explain it well, but my fiance (who has an 8700c still) held the 8703e and said it felt "lighter" in weight, and the curves- though not very noticeable- did kind of make her feel like the 8700c was more of a brick.

I know it's hard to explain, and my points probably don't make sense, but I can see where he's coming from. Trust me, a few drops down the line (like I've experienced) will surely make you see that there isn't a difference in that 'solid as a rock' feeling you had with the 8700c. Although, these devices are not nearly 'tankish' as the 72xx series. Those things could've made decent baseballs or small riot control projectiles.