Best Personal Size Backpack??
 

What is your favorite Personal Size Backpack??

I like the Tom Bihn Synapse 19

I like my Tom Bihn Synapse 25, but not as a personal item. For a personal item i use B&R expandable cabin bag or a montblanc large brief that's more like a tote bag. For some reason I don't like backpacks for airline travel much.

My go-to is the Peak Design 30L. Admittedly, it's a bit large, really, for EDC use, but as a Do Everything sort of backpack it's been perfect for me. I've used it for international and domestic travel as a carry-on, as a hiking backpack for day hikes, a weekend/2-3 day bag for short road trips, work backpack when I need to go to meetings in the field, etc. That said, I also will sometimes carry a good bit of camera gear so that is why I originally landed on that bag, though I DO use it without carrying any camera gear as well and have loved it.

I'd probably be OK with the 20L version too, but the 30L has the expandability I wanted to be more of a Do Everything bag.

Nomatic 14L

It will meet requirements for under seat on United and most carriers.

I have been using the Everki but you did not say why you want to use. I've had it about a year and no wear, no tears, no issues.
This one is great for my laptop as well as other things. Not good for a clothing backpack.