I have been using a 128GB SanDisk Ultra Fit USB 3 device with my MacBook for a while now and have really grown to love having all of my Dropbox available without using up my SSD disk space.
I've recently purchased a 128GB Micro SD card with an SD adapter in the hopes that I can free up a USB slot.
I'm looking for recommendations as to which type of filesystem formatting I should use. I started out with exFAT and felt like it was a little sluggish, so I switched it to OSX Extended (non-Journaled) and I'm not seeing much of a difference.
From what I could find, some people said that using Journaled with a Micro SD card might cause too many writes and could wear out the life of the Micro SD card.
In my case, I'm primarily using Dropbox for file storage and some app usage. I use it with 1Password, but don't do a lot of heavy operations like working directly on Photoshop files.
EDIT: Here are the specs:
MacBook Pro (Retina, 13-Inch, Late 2013)
2.4GHz Intel Core i5
4GB 1600 MHz DDR3
MicroSD to SD Adapter:
BASEQI aluminum microSD Adapter for MacBook Pro Retina 13"