I watched the first three episodes yesterday, it's nice so far but nothing special (very few shounen are at the beginning so I expected it), the three main characters are likable enough but I hope they tone down Kurapika's and leorio's arguing, it's exhausting, the scene in the back room elevator went on too long.
Cute little cliffhanger at the end of episode 3, who was disqualified? It has to be the guy who lost his arms (I'll find out soon enough, I'm starting episode 4 right after this post)
The exam stuff is obviously just a way to introduce the characters and world, I assume most of the characters that were named in episode 3 will become important. The evil clown guy will most likely switch sides and join Gon, he's too obviously evil at this point, I bet thats a ruse and he's secretly a nice guy (shounen nice, not nice nice, he's still going to take your arms but he won't stab you in the back like the Tonpa guy) and the opening already spoiled me on the white haired guy (Kullira?) as the fourth main character. I guess the computer nerd will be out soon, his computer knowledge won't help him if he doesn't have time to type and do research, he doesn't seem to be able to make quick decisions.
The three brothers are the first arc's villains, one is taken out soon and the other two blame Gon and friends and go after them, I bet that's when the clown comes to the rescue because the brothers are breaking an exam honor code or something.