Not bulky but uber-durable!
I purchased the STM Goods case for the iPad Air 4th gen 10.9" after trying out a couple of others from UAG (Metropolis & Lucent models). While other models SEEMED more protective (and bulkier) due to materials and thickness in certain areas, the lack of protection in other locations caused me concern. I have seen hundreds of the STM cases used by middle schoolers hold up to daily use for 3 school years. Floor drops, desk slams, and bounces down stairs nearly always resulted in NO damage!
I do like the holder for the Apple Pen so that charging can still occur while closed but I do wish there was a bit more protection for the tip while charging. When not charging, you can simply slide the pen towards the "eraser" end and the tip then does "recede" into a more protected area.
This company's record for resale value of its products is noteworthy. That, and the longer guarantee provided really make STM products stand above the competition, in my opinion.