Version 4 was my favorite as well. Excellent theme, icons, and an overall
level of polish. I loved the level of opacity on the bottom panel and the
menu.
It was so pretty that I instantly installed it on my brother's laptop which
thankfully worked out of the box (video, audio, wireless) and he could surf
the web, listen to music, and write documents for school in LibreOffice with
no hassle.
I'm a very visual person and I can honestly say that the Gnome 2 based
Trisquels were on par with the non-free ones in look and feel.
The magic was lost with Trisquel 6 onwards as we lost most of the visual
flair and I couldn't customize my desktop as easily.
Now that MATE is supported and ready to shine, its time to seriously consider
it default or at least offer it as another ISO alongside the regular and mini
versions.