I took a grad seminar on the Philosophical Investigations, and it was one of my least favorite courses of my entire time as a grad student. I really just don't like the way Wittgenstein wrote and I had a hell of a time trying to figure out what his arguments were (insofar as he had any arguments, ordinarily construed) and why he was making them. Part of the problem was that the professor who taught the course really wasn't much of a help in understanding this stuff. Everyone who took the course was way out of their depth, including me.
I'm "trained" to read conventional academic, analytic philosophers and to write like one. Moreover, I adhere to the conventional "Tell them what you're doing and why you're doing it, do it, and then tell them what you did" style of writing (I have to anyway, as this is the standard in college courses and academic writing generally.) I try very hard to avoid any kind of obfuscation. Wittgenstein completely subverts that, so reading him is often an infuriating experience for me. For a striking contrast in early analytic philosophy, check out G.E. Moore's Principia Ethica: clearly written and clearly argued (and a brilliant piece of philosophy to boot). That said, I haven't read the Tractatus, so I don't know whether I would find it more approachable.