First of all, the alphabet isn't that different. My first language is Japanese (although I barely used it between the ages of five and twenty) and I also know a lot of Mandarin and Korean, and a little Arabic and Cantonese. THOSE, my dear are different. There are even a few letters in the Cyrillic alphabet that look and sound almost exactly like the way you say them in European languages, just with a different accent; "a" for example, is the same, sometimes like "fall" and sometimes a little more like "cat" depending on the word.
If that's your biggest concern, you should know that Rosetta does have specific lessons to teach you how to read and spell accurately. Also, it's the only program with voice recognition software to coach you on speaking and pronouncing correctly.
I don't know what the other person means by "It only teaches nouns" because I distinctly remember verbs less than one minute into the program and being able to do about twenty types of sentences in less than half an hour. It has specific lessons for grammar, reading, listening, pronunciation, conversation, and it even teaches you how to type Russian, which they don't even teach in most college courses.
It has a six month money back guarantee anyway, so even if it doesn't work for you, you can just get a refund. Just make sure you buy it directly from Rosetta Stone company and not from some store or other website because then the guarantee is void.