[ewphoenix123]

So, I finished installing the new sd and ran a few tests.

# Page turn speed is pretty much the same, depending of which times I compare.
It may be slightly slower, maybe ~5% at max, but that can as well be a standard deviation, we are talking 50 page turns in ~33 instead of ~32 seconds.

So no benefit here.

# Browsing collections, books seems slightly faster, but it was never slow in the first place.

# Opening books for the first time feels a little bit faster.

# Extra space of 15gb seems to work, no problems with books not showing up as other user reported with some sd cards.

# Transfer speed computer (calibre) to Kobo increased ~3x fold, that includes sending/deleting books and updating metadata

# Updating of the database on the Kobo after adding new books is 2-3x faster

# The fetching of book covers on the Kobo after the transfer is almost instantaneous now.

I don't think upgrading really benefits the casual user, Kobo put a pretty decent SD in my GLO model and the reading experience by itself won't improve with a new card.
Everyone who wants to maintain a big library on the reader, on the other hand, will experience a noticeable speed increase when adding or replacing books, and of course a much bigger storage size.