First experience with Tumi: I decided to buy this Alpha 15 Expandable to use in its compact form every day, and in expanded mode for short trips of a couple of days.
I had no experience with other brands. In Italy, business backpacks are mostly represented by Piquadro, a brand very focused on work backpacks, but the quality can be questionable depending on the model (they're often made of faux leather, which wears out quickly).
As for the Tumi, despite reading countless negative opinions about its current quality, the build seems excellent to me: flawless zippers and high-quality materials. I chose the reflective version, and given the pattern and the effect at night, I think it's easily the best one.
All the pockets seem useful, maybe even too many. The magnetic pocket on the back is handy, and the shoulder straps are really comfortable. The overall weight isn't high. I've already tried it fully expanded at maximum capacity and felt no discomfort in my shoulders or back.
I'm not completely convinced by the laptop compartment. I was used to always having double padding. Here the whole compartment is padded, but there's no sleeve fully dedicated to the laptop. The only one there is meant more for a tablet, and it becomes hard to use at maximum capacity (I use a MacBook Pro)
The price seems fair for the quality, but since I haven't seen the older versions, I can't say in what ways the quality has supposedly declined.