Homestuck is one of those things where I really enjoyed it and it's had a lasting impact on my personality and sense of humour, but if a friend of mine asked if they should read it I would probably say no.
Because it's just so stupidly long and intricate, and at times it feels like it's purposefully boring. If you have a job or just like a life in general there's no way to read Homestuck properly, because it'll take up like 4 straight weeks of your time.
You really had to be in the right mindset to get into Homestuck. You had to be a Tumblr user in 2013 that got bullied at school. That turned out to be a surprisingly large demographic.
Undertale was basically the spiritual successor of Homestuck. It kinda did what Homestuck did, but made it available to a large audience. Sure, the story is nowhere near as rich, but you still get that unique Homestuck vibe from it.
So... If you've never read Homestuck or played Undertale - go play Undertale. Don't bother with Homestuck. Unless you really, really, really, really, really, really, really, really, really, really, really, really, really liked Undertale. In which case you should read Homestuck.