Hi Ryan, I'm learning myself but hear me out here. If you're interested in learning Mandarin but with traditional characters, you can simply get textbooks from Taiwan. Some of the popular titles coming from Taiwan (that also include English annotations) include "Practical Audio-Visual Chinese 實用速成華語" (5 volumes + audio CDs, each textbook with a separate workbook) and "Far East Everyday Chinese 遠東生活華語" (I think 3 volumes with audio CDs). If you want to learn Hong Kong Cantonese with traditional characters, there are several good titles for English speakers published by Greenwood Press (green-woodpress.com). I haven't studied any of the non-Mandarin dialects of Chinese (such as Taiwanese Hokkien or Cantonese) but my understanding is that Mandarin is the easiest variant of Chinese and that dialects are generally more difficult.

It depends on your environment. Cantonese is more difficult since it has 9 tones vs the 4 tones of Mandarin. On the other hand, Cantonese uses much Classical Chinese in their speech but slang is also abundant. The grammar can be slightly different and there are more characters in Cantonese not found in Mandarin. Idioms, phrases etc can be as varied as Aussie English vs US English even though we use the same grammar, alphabet etc. Using simplication of character is not a big deal. You can learn both easily. Able to use the language in the right situations is important. For example, you get better service when you speak Cantonese in a Cantonese restaurant. They may give you an extra wonton, free desserts and small things like these.

Well, first, strictly speaking, mandarin Chineses is not a "dialect". It's just like RP (Received pronunciation) in English or sort of "standard English". It is built on our north dialect (Chinese) and works as our offical language ("standard Chinese"). It is not only popular but an requirement for every Chinese people to learn, so as a beginner, you'd better choose the mandarin Chinese，in terms of accent (pronunciation, tone, grammar etc.). Then, when it comes to the "version " of the Chinese characters. There is no doubt that the traditional characters are easier to understand and memorize, because, compared with the simplified Chinese characters used in the mainland, they represent more rules of their creation. Thus, you may choose any "version" you want. However, if you didn't learn any simplified characters at all, you would be in trouble with communication when you travel in the mainland, China.

Mandarin is created on the basis of Beijing dialect

Ni hao ! I think Beijing Hua more easier and more authentic.