As long as they perform well no loss there, the batteries are probably the same or they can't name it 510 or not? I don't much care if Joye makes it or some third party as long as it's quality.
Mixed results on the "L2", some people say it's fine, others...not so much. Here are some threads:
http://www.e-cigarette-forum.com/forum/general-e-smoking-discussion/54478-l2-510-clone.html
http://www.e-cigarette-forum.com/fo...-discussion/55432-l2-510-battery-warning.html
http://www.e-cigarette-forum.com/forum/e-cig-technical-issues/55052-leaking.html