There really are a lot of factors, and the "weight factor" is very subjective. For example, do you hold your iPad Pro on the long edge or the short edge? Have you tried holding it on the short edge for long periods of time, e.g. 10+ minutes? Still, I'd agree that it depends on the individual.
There are a bunch of points that need to be considered when comparing tablet handling with laptop handling:
- You will rarely hold a laptop in your hand for long, and you'll always hold it in Landscape (long edge), so there's a definitive torque advantage, although when "opened" the Center of Gravity (COG) tends to shift away from you.
- Tablets can be held either portrait or landscape, with portrait imposing a significant torque penalty because the COG is further from your hands.
- The primary means of input for a tablet is touch, not a keyboard, so you'll often need to hold it in one hand while using the other to touch the screen. This immediately increases the torque because the distance now the diagonal from a corner to the COG, not from edge to the COG.
This makes torque all the more important when considering the design of a tablet.
If we compare all 3 iPad sizes and weights right now from the perspective of holding them in Portrait (this is my preferred way of handling my iPads when not resting on a table):
- The iPad mini has a COG 10cm away, 0.30kg for a torque of ~0.030Nm
- The iPad Pro 9.7" has a COG 12cm away, 0.44kg for a torque of ~0.053Nm
- The iPad Pro 12.9" has a COG 15cm away, 0.72kg for a torque of ~0.11Nm
Taking the iPad mini as the reference, the iPad Pro 9.7" is 1.46x heavier and the iPad Pro 12.9" is 2.4x heavier.
Torque wise, the iPad Pro 9.7" is 1.77x "heavier" and the 12.9" is 3.67x "heavier".
Assuming I didn't make any mistakes with my math, the torque differential because of size affects handling significantly, although it may or may not bother individuals differently. The current 12.9" is 2x harder to handle than the 9.7" in portrait mode even though it is only 1.65x heavier.
I don't insist that the iPad Pro 12.9" is too difficult to handle - that is really very subjective, but I think people should really pay more attention to torque in ergonomics rather than simply weight - it
does matter.