Well, I’ve got a 25 and it’s on the limit of what I want to carry on a bike, but you may be broader, narrower, have different perceptions of what’s comfortable/acceptable. But if you look at the dimensions, the width is the same, but the 30 is slightly taller and deeper.
I wasn’t being facetious btw. Everyone’s a different shape. I think the 25 is a great pack on and off the bike, but I’d find a stockist, get them to put some kit in each and see what you think. HTH – dimensions off the Osprey web site.
Escapist 30 Dimensions
Dimensions are shown as length (height) x width x depth
S/M 50x25x28 cm.
19 11/16×9 13/16×11 in.
M/L 55x25x28 cm.
21 5/8×9 13/16×11 in.
Escapist 25 Dimensions
Dimensions are shown as length (height) x width x depth
S/M 48 x 25 x 24 cm
18 7/8×9 13/16×9 7/16 in.
M/L 52 x 25 x 26 cm.
20 1/2×9 13/16×10 1/4 in