Questions on Note 5

Hi,

I'm planning to buy a Note 5. I would really appreciate if I could get answers on my doubts :

1) Are there any technical issues in dual sim version compared to the single sim version?

2) Are both versions having the same specs apart from dual sim option?

3) Which is the best version (international) to buy among the two?

4) Is it true that dual sim version could cause potential health risks in the long run due to double reception power?

5) Is there going to be a version two or second production of current existing models with upgraded firmware and tweaks or rectifications?

6) Compared to other mobiles with 4GB Ram, how is the performance of Note 5?

Awaiting reply,

Thanks.