When it comes to eye candy I believe less is more. I set the opacity between 80 and 90% when i used Compiz with XFCE in the past. I think Compton is much lighter on resources than Compiz.
It lasted about 2 months. I just turned off the transparency, because sometimes it got harder to read the code, especially when I switched to tabbed windows (alt-w in my configuration) and there was another text file behind the terminal.