Probably a wishlist item, but, it’d be great if cryoSPARC could import (and even use internally) HDF5 files. MRC is getting a little long-in-the-tooth and HDF has quite a few advantages over MRC now. It can store basically unlimited arbitrary header data without breaking files, supports zlib compression, and is seeing increasing adoption by the Cryo-EM community, with SerialEM, IMOD, Chimera, ChimeraX, and EMAN2 all supporting HDF.
In particular, HDF when combined with bit truncation seems like an excellent way to wrangle large data sets and particle stacks. While .tif supports compression, particle stacks in .mrc/.mrcs are actually turning out to use the largest chunk of storage. Specifically, I think this article highlights the very nice capabilities of HDF and all its advantages: