As I understood EAP-TTLS and PEAP share same level of security when implemented in wireless networks. Both only provide server side authentication via certificate. 

The drawback of EAP-TTLS can be non native support in Microsoft Windows so every user has to install additional software. 

The benefit of EAP-TTLS can be support for less secure authentication mechanisms (PAP, CHAP, MS-CHAP) but why would you need them in modern and properly secure wireless system?

What are you opinions? Why should I implement EAP-TTLS instead of PEAP? 
Let's say that I have most Windows users, medium Linux users and least iOS, OSX users.