Features such as PAVP via Intel Insider are not accessible in the current implementation (version 2) of Intel Software Guard Extensions. Access to PAVP and other powerful features of iME such as iAMT has been restricted to Intel and Intel Partners (M$, DoD) through obscurity and no available documentation. However, that being said, there are several white papers authored/co-authored by Intel employees who do make use of these immensely powerful features.
iSGX (nor any current technology that is known to the public) is capable of ensuring input CIA properties (without utilizing Intel Insider/PAVP to display a digital keyboard, transmitted via direct bus to NIC/eth.)
Other security technologies, specifically Sanctum does provide different coverage than iSGX but there is no "unified" security technology that is a one-size-fits-all solution.
iSGX's main PoF is poor security implementation by ISV's/enclave writer's. That being said it is better than TrustZone, TXT, XOM, Bastion, Aegis and Phantom in regards to the ratio of return:implementation cost.
edit: additional information
Hoekstra and fellows at Intel have created a PoC secure browser plugin that utilizes an enclave.
Use of middleboxes that are hardened and have iSGX support can be used as a proxy as well to limit exposure.
IIRC can't it communicate directly to the keyboard,screen and the network?
Besides DRM, this is probably the next best killer feature for the system if it's as secure as they claim.