The following is based on my own experience (not a categorical statement).
- No matter the claims, I find all to dry out unless the cap is returned to the barrel immediately (I hold the cap in my non writing hand).
- I have found the premium gel G2 Pilot refills (about $2.00 for 2), to write and perform just as well as the 5888. They are also compatible.
- I sell all pens with a 5888 because I feel it looks like a premium refill (even though the client can't see it). However. in my experience the G2 performs just as well.
- I have purchased some 6040s and they dried-out very fast and their tips got smushed even the I have a pretty light hand.
- I have not had much success with the Sneider or Hauser refills, but many find them just fine.
Remember, this only based on my experience. Take it for what it is worth.
Enjoy your research!
OK, back to my day job!