I agree with the "if I wait until I think my art is good enough I'll never post anything" sentiment expressed above. I basically looked at some of my favorite webcomics that have been going for 15+ years and when you go back and look at their early work it's nearly unrecognizable, so I figured "screw it, if they can do it then so can I."
Here's Zonk and Miguel in their first appearance together vs one of the last times they were in an episode together:
And this is Zonk and Nicole during their first meeting vs this week's episode:
So yeah, over the last two and a half years things have improved dramatically IMHO. I'm still complete shite at backgrounds but I choose to believe that nobody reads my comic for the backgrounds anyway...
Edit: But to answer the actual question I wouldn't say there's a huge change style-wise, it's mostly just in effort and confidence. My early episodes definitely fell into the "screw it, who cares if it sucks" category so they're all sketchy and messy, and these days I'm actually shading and trying to make things look a little cleaner. You can probably still tell that I'm inking very quickly and haphazardly but it's slightly more pleasant to look at.