For me ( and this is a biased opinion ) Farscape is absolutely one of the best if not finest space opera/fantasy show for last decade. Characters were written with a wonderful touch and played with amazing interpretation. Chemistry and interaction between characters are incredible. Character development is quite good. Not to mention best romance story I have ever seen in sci-fi genre. Farscape universe is crazy , funny , weird but also dangerous , gritty and sometimes dark. High production values also help a lot... Yes there are some stinker episodes like "Taking the Stone" or "A Prefect Murder" but that is not an exception in other successful sci-fi franchises either. And even those bad episodes add something to universe of Farscape , change the characters , outlook and merge with rest of series. They are not meaningless stand alones. (mostly)
I only regard two other series in same level with Farscape. Babylon 5 and Battlestar Galactica. They have different thames , plots , messages of course. But about orginality in sci-fi those three series are perfection for me.
You pretty much summed up my feelings about Farscape.