Finally I found a browser that doesn't choke on the github download link.
First impression: Surprisingly "normal" and uneventful installation. Nice and uncluttered desktop (no conky ), no serious bugs and good speed.
Main reason why I wanted to try Vanilla was to find a working Xsane installation (F96-CE-3 wouldn't detect my USB scanner).
Unfortunately Xsane appears to be not installed at all, though the xsaneshell script exists. Will it be included in the ISO some day?
In general the selection of applications is a bit scarce but that's OK. Apart from Xsane there is nothing I miss.
Compared with applications the number of installed fonts is impressive. However all installed fonts - apart from the emoji fonts - cover more or less the same limited range of characters. In other words they are redundant. What they lack is the wide range covered by Puppy's staple font DejaVu Sans. Is there a reason why this font is not installed? So far I've never experienced a Puppy where this font is not present.
The first encounter with the insufficient Unicode support was the "Open File" dialog in Geany. It uses the GTK3 file chooser, and this chooser seems to have a bug. The "Modified" column should display the time for recently saved files in format HH:MM. The separator should be an ASCII colon. However here it uses Unicode U+2236 RATIO , which looks very similar like a colon and it not supported by any of the installed fonts, DejaVu Sans would support it, but my point is that it should really be a colon like in the GTK2 choosers.
In order to see the differences between the OOTB fonts and when adding DejaVu Sans I used my own Unicode tool. Apparently there are huge gaps in character support. What is also apparent is how problematic the colorful emoji fonts can be when they overlap with the range covered by DejaVu Sans. Sometime the emojis "win", sometimes DejaVu. The user can never be sure what the system will pick. IMHO colored emoji fonts should never be installed by default. If the user loves them he/she can always install them afterwards.