For me personally, "Slaughter On Muunist" was where the series really started to take off and when I knew we were truly witnessing something special.
"Crisis on Abridon" was a great story and a great start. But then there was a long delay until "Underground Resistance", which I thought was a slight let down, as the focus was more on the events of "Phantom Menace" with Rykrof as a by-stander.
"Anti Jedi" was very cool, but I felt the ending was a bit odd - with Shundi just snapping his fingers and putting the characters to sleep just when some real conflict was about to heat up.
But "Slaughter" was an excellent chapter and a harbinger of things to come - action, intrigue, great characterizations & complex storylines. That's when I knew Chewie & Rykrof weren't just some passing fancy. They're the real deal.