Homestuck up to Cascade is an amazing story, with one excellent intermission and one decent intermission.
Homestuck in between Cascade and Game Over is also a great story, albeit with a lot more slow sections. It's a decent sequel to the first part.
Homestuck after Game Over is...well, there's some good moments, and Collide was definitely cool for what it was. But it definitely didn't live up to the first two parts.
The thing is, the low quality stuff in the end doesn't change the high quality stuff at the start at all. Nothing can take away the amazing experience that Acts 1-5 gave us.