Rosetta Stone is very, very good. Version 3 has the reputation of being an improvement over releases. Not sure, but the biggest improvement might be in the voice recognition.
The software is much better than the company, in my opinion. Load it onto the computer you like best, because if you crash or remove it, you are just stuck. If you get tired of it, or get all the benefit you hope for, you are not going to sell it, as it is about impossible to install it on a second machine.
Watch their pricing, by the way. It is somewhat discounted on Amazon and through advertisements placed in magazines like The Smithsonian. Do not pay full list price. More cautions on the pricing. Level one is not too badly priced if you use Amazon, but if you want further levels, you are stuck. The package price for 3 levels is high, but substantially lower than buying levels 2 and 3 separately. In other words, if you want all 3 levels in a package, get it all at once. Otherwise, you will likely end up buying the complete package, and throwing away level 1 you paid so much for.
There is an advantage to buying direct from Rosett Stone direct from the publisher. You get a money back guarantee, though I don't recall the trial period - something like 60 days, which is no way time to complete 3 levels, unless you are pretty familiar with the language before you start.
I suggest you look them up on Amazon, and carefully read the reviews. Some of them are pretty thoughtful.
I've no experience with either Arabic or Mandarin, but I imagine all versions are comparable in content and methodology. Like I said, the product is good; the company is a bit difficult.