I too have little tolerance for excessive branding, so when I discovered that Moleskine puts out blank memo books with the exact same trim size as Field Notes', I opted to give them a try and I'm sure glad I did.
Blank brandless cover aside, these Moleskines are thread-bound compared to Field Notes' cheap saddle-stitching (staples). The interior paper is quite superior with the ink from my fountain pens never bleeding through as much, plus it is a serene cream tone which is much easier on the eyes. Half the pages are perforated which I imagine will come in handy if ever I need to slyly leave someone my number (haha, no but y'know, sometimes you want to write something down for someone). Cover stock is heavier than Field Notes' so it doesn't curl up and get that worn look as quickly, and it comes with a back cover pocket thingy which I find is always very useful.
And honestly, if it didn't have all these advantages, just the absence of obnoxious branding alone would've been enough to win me over.