Hitman Reborn was initially recommended to me by my friend. However the story looked dull and uninteresting to me, and I was also not sure if I would like it (I watch anime like Bleach, DGrayMan etc.) Thus I started off with the manga. The first thing I thought when I read the manga was "WTH is with that stupid looking baby? The main character is also so badly drawn!" However, after reading a few chapters, I got hooked and finished 100+ chapters in a day. I decided to give the anime a try, as I wanted to see how well the characters could be brought to life.
Story:
The only thing that prevented me from giving a 10/10 was that the story took waaaaaaay too long to start! Sure, the first 20 episodes were amusing and had me cracked up, but there was no real storyline to it. The anime was also inferior to the manga in my opinion, as they had more fillers and also took out the guns and knives (and Tsuna's reactions to them) that would have made the whole thing even more hilarious. However after that the real action starts, which had me hooked all the way! The storyline is extremely unique, and Tsuna's irritating underwear transformation thing became less frequent, and finally disappeared altogether :D It is also way different from most shonen anime, which usually only consists of blind fighting and no development at all. In all, an amazing storyline! (After the first 20 episodes, that is, but don't skip till there, have a look at the characters!) :DD
Art:
I would give it an 8/10, as the characters in my opinion were not very well drawn. The characters usually look fine, however weird if shown from different angles. However the animation was okay, the fighting scenes were well animated, and I especially enjoyed looking at Tsuna's weird faces whenever Reborn is up to his antics again x)
Sound:
In my opinion the OPs were the BEST! Drawing days (First OP) had me addicted the first time I listened to it. Except for OP3 (Jumping Days I think), I just didn't like it at all D: The voices for the characters in my opinion were well matched and I just loooooooove them, but Tsuna's voice is still a little weird to me (Too high I guess). The BGM, however, was AMAZING. It totally brings out the mood in whatever is happening and will have you paying attention to it in spite of the action going on! Each character's theme was also awesome, especially Hibari and Gokudera's theme.
Character:
In all, the characters were what makes Reborn a kickass anime! :DDDD It is amazing how some characters who only appeared for comic reliefs could get so serious and awesome whenever they needed to! The way the characters have matured is the main factor that kept me hooked onto the series. The transitioning is so subtle, you wouldn't even notice how much they've grown until you think back and remember how they used to be (Remember whiny old Tsuna?) The different personalities that match each of the characters and the way they follow such an unlikely boss is truly cool! :DDDD
Enjoyment:
I enjoyed Reborn as a whole, except for the first 20 episodes (It's TWENTY hello) but the storyline and arcs later on made up for it, and also the character's ridiculous antics which really give the series a light feeling, yet serious when needed.
Overall, if you're looking for a new anime to watch, try Hitman Reborn! It may seem boring at first, but persevere on! Until the main story starts, there is a good chance that you'll be hooked too :D And the storyline is amazingly unique, I've never seen any anime like it before xD