It has been stated by many that correct Arabic pronunciation would be 'Raas.'
The correct Arabic pronounciation is Ra-us, though <PERSON> is close enough. wiki
This is this bit from Batman Beyond in which <PERSON> says "<PERSON>" and is subsequently corrected by <PERSON> to say "<PERSON>." This made it a sore spot for me when new Batman trilogy decided to use "Raas."
https://www.youtube.com/watch?v=TULYXGYz02c
There are several unsubstantiated (or cited) claims that the creator used and intended 'Raysh.' Indicating a preference for the Hebrew pronunciation for the word.
The correct [Arabic] way is closer to 'rahs', the way <PERSON> (the writer who created the character) intended it to be said is 'raysh'. The the DCAU went with 'raysh', the <PERSON> movies went with 'rahs'. reddit
On the embedded video there is also a dubios comment which states:
The creator of the character meant for the pronunciation to be the Hebrew pronunciation <PERSON>, probably because of the whole <PERSON> [pit].
Then there is this quote from Executive Producer <PERSON> from Arrow.
One key issue I wanted to bring up, because it came up last season when I wrote about that third episode, is the pronunciation of <PERSON> first name, which has traditionally been something close to "<PERSON>" or "<PERSON>" when referred to colloquially, but becomes something closer to "<PERSON>" or "<PERSON>" when savvy fans discuss him.
"The beauty part of what you guys do is you just have to type it and it's the same spelling even if it's a different pronunciation," <PERSON> laughed. 167
"Basically what we decided to do, and I think you sort saw this in Episode 2.13 when <PERSON> came to town, is we basically honored the two different pronunciations, some of our characters saying '<PERSON>' and the ones sorta more in-the-know say '<PERSON>' and that struck us as a very reasonable compromise. There are clearly two different schools of thought and we wanted both to be represented."
So he seems to think '<PERSON>' (or '<PERSON>') is the more correct pronunciation for the name.
Update
At a recent San Diego Comic Con panel there was some discussion about "<PERSON>" versus "<PERSON>" from <PERSON> and <PERSON>.
He explained why some characters pronounce "<PERSON>'s" "<PERSON>" while others say "<PERSON>." "If you are part of the League of Assassins, you say '<PERSON>.' It's a sign of respect and the proper way to pronounce it. If you are outside the League and you're rogue, as a sign of disrespect, you say '<PERSON>.'" That understanding came about because the actual pronunciation was not clarified on the set until episodes with the "<PERSON>" pronunciation had aired, so, "we had to create a mythology."
Final Verdict
At least for Arrow, "<PERSON>" (or "<PERSON>") is the correct pronunciation, while "<PERSON>" (or "<PERSON>") is a more derogatory version. In the DCAU, "<PERSON>" is also the correct version.
For the cinematic Dark Knight trilogy, the correct pronunciation is "<PERSON>." 167