I mentioned to my friends that I wanted to try out Diana, they all said that she's horrible, but didn't really explain how. Is this true? Is she a decent champion? She looks really cool and fun to play as. Can I get some opinions on her please?
Her win rate drops the higher the Elo you look. The problems I see she has are that she is very unsafe and so susceptible to gangs because she's melee and has no escapes meaning to trade in lane she puts herself at risk everytime. She also has a hard time in a seige. And if she gets peeled she has a bad time. Is she horrible: not really Is she weak: absolutely Is she fun: hell yeah
She's on free week right now, go try her out :)
Glad to hear some positive words, I came in here expecting to see her get thrashed by public opinion. Diana is my favorite champion in the game, and a Champion I feel really strong on, Even when I'm a bit worried about how well i'll perform I've always done well enough, I've never been on her and just felt like I couldn't do anything to my opponent, and often feel pretty dominant.
This is my personal opinion, but I think if you're enjoying a champion you can do good on them despite the champion. So if you want to try someone out, do so. Especially if they show up on free week. I've found more champions I didn't think I'd like, but played them and enjoyed than I have the reverse.
Also as people here said and I've heard a few times now, the relation with her and Akali in style, Personally I feel if you put me on Diana I can do good, put me on Akali (whom most if not all would say is better) and I will be pretty underwhelming. (which is a lack of skill on my part, but it's more of an example how you can do better on a champion perceived to be weaker based on an individual)
I typically build her like Technomancer Jay's sustained damage though I tend to get a few of the "burst" items later on.
You can poke with her Q and farm some (if needed), sometimes at the same time. Being a curved skillshot her Q can hit in ways people aren't always as prepared for. Her W is a nice shield that allows you to trade pretty favorably when you're close up, and between her E and R she's really good at sticking to a target. And even if you use her Ult without getting the reset off it has a nicely short cooldown.
As MrBuffington said, she's on free week. Check her out and see for yourself.
She's one of my favorite champs, and was my first one bought. As long as you learn when to go all in, and when to not blow your ultimate twice, she's very good.
Diana is a champion that you can build for either high burst, or sustained damage. Her laning phase is typically a bit weaker, using your Q and W effectively, you can trade alot more damage than your opponent expects. Her weaknesses include being able to be poked from range, and having no escape from fights. However, she makes up for this with up front damage with her full combo (Q -> R -> W - > E, repeat unless you want to use R again to put on cooldown). I would definitely recommend playing her, but you must remember, her mid game is when she is strongest (unless you build her for a bit of late game like me)
For builds, if you're going for high burst, go for 
, this gives you a sheer amount of AP, along with some HP, armor, and penetration. The only down side to this is you lack sustained damage while your Q R combo is on cooldown.
For sustained damage, go for 
(if jungling) or 
, go into 
. At this point, you have a decent amount of AP towards the mid game, and it compliments your passive really well. As soon as you get a , you hit an even bigger power spike. As for a final item, decide between 
or . I hope this helps!
She's an assassin not unlike Akali. She can be difficult to use but I have seen people destroy with her and get destroyed while using her. It's all player skill and, as I said, she has a steeper learning curve than some other champions.
Like Akali, she benefits heavily from an AP-oriented build. Like Akali, her ultimate allows her to chase foes by dashing to them and dealing magic damage in the process. Like Akali, her Q is an effective ranged poke that places a mark on the enemy.
Unlike Akali, Diana is effective as an upfront attacker in trades. Whereas Akali seeks openings to dash in, burst, then hide to escape and wait for her next burst, Diana will often activate her shield which deals damage and run straight into combat, using her pull to keep enemies engaged with her and then chasing with her ult when they flee.
The extra skill comes into play when keeping your Q mark on the enemy in order to continuously use your ult without cooldown. Also knowing when to disengage is important since it can be hard for her. She is a hard engage assassin with good burst damage but better suited to more protracted fights than Akali. I say Akali because she's just a good analogue and well known melee assassin.
She's ridiculously fun to play, definately reccomend her.
As far as balance, she is not in a weak spot right now as far as my expirience with her goes although poeple have very mixed feeling about it. I'd say she is good right now.
I don't think 
horrible, it's just that her playstyle revolves around locking onto one target with your Q + R +R combo, and if you happen to miss your Q, it kinda dampers you're ability to go. Landing Q allows you to use your ult twice, so, if you miss Q, you lose out on some dmg.
Nonetheless, Her Q is really fun to use and is a great poke tool in lane, and can allow you to hop over walls with your Q+R combo. Plus, your Q also can grant vision if it strikes an enemy in a brush.
She's a mix between an assassin and a brusier, so there's a lot of item builds that you can mess around with. I usually only play her mid, and I go x2 
and after I try to get afterwards, since I also have the chance to act like a mini orianna ult with my E for my team.
I think she's a decent champion, and if you're really interested in trying out diana I say go for it. =)
If you ever manage to get extremely ahead with diana, you feel like you can fight anyone because of your shield xD She really is fun to play.
