Hi Simona
Thanks for the comment. I've written an up-to-date blog post about this subject: http://www.nanjingmarketinggroup.com/blog/alipay/third-party-payment-opt...
The latest blog is specifically for payment options in China. Can I ask, do you want to use this service for Western or Chinese customers? If Chinese I'd recommed Alipay. If Western I'd recommend having both payment options on your website. What I'd say about Alipay is that it's becoming more well known especially after the Alibaba IPO. This will only increase the trust and presence of Alipay as a third party payment platform.
If you'd like more information specifically about charges and transaction costs then I suggest you contact us directly at info@nanjingmarketinggroup.com. One of the team will be able to help you in much more detail.