I have digi padding on my fullsuit ( I didn't make it)and a huge foam carved tail and it is HEAVVVVVYYYY. The suit weighs like 20 pounds on its own, I swear. My digi padding is four pieces, two thigh pieces and two calf pieces, I have to put them in the suit before I put it on and wear leggings so it doesn't irritate my skin. The padding is carved foam blocks and even though they aren't very heavy on their own, they do weigh the suit down. I can still walk around for quite some time, and dance in a limited fasion, but I am very restricted. It's uncomfortable to lay down partly because of the huge tail and padded legs, but also because of the huge stompy feet. I can't crouch down without stretching a lot and it kinda hurts. Can't really touch my feet. I have to walk with a waddle and if I try to sit in a chair my calf padding pushes my legs out uncomfortably. I still love it and get tons of compliments on the leg shape, and it feels really cool to stomp around in a huge padded suit but plantigrade is a whole lot less hot and limited in mobility. Also for digi legs you have to make the feet bigger to match the legs so they're heavier and more cumbersome too. Keep in mind too that a digitigrade suit takes much more space to store due to the padding, bigger feet, and more fabric on the suit. There's pros and cons to each for sure.
If you're curious, here's a pic of my suit:
And like fayv said, padding always look quite right, on my suit for example the calf wiggle around when i walk too quickly and i have to adjust them a lot and it looks funny. It's really hard to get it perfect. and usually looks better if the crotch is dropped down and padded too (in my opinion), like Havik (http://25.media.tumblr.com/tumblr_mbe98uZNad1qawcnzo1_500.jpg
) or Lewis (http://25.media.tumblr.com/tumblr_md0b7z2eAy1rjz0wgo1_500.jpg