看看真实的VMware View 与Citrix XenDesktop对比。
 
用户体验作为虚拟桌面的关键因素，看看VMware View如何立于不败之地。
 
对于测试中暴露的差异，您也许会觉得困惑。其实当您了解完下面这些，就全明白了。
Citrix 的 XenDesktop 使用的是 PortICA 协议，而不是 XenApp 的 ICA 协议（因为 ICA 是基于 Terminal Server ， PortICA 基于 XP 。两者底层架构相差很大，必须重新实现）。
XenDesktop 的表现其实是不如 XenApp 的。不过很多人被混淆了。把 XenApp 的光环也戴在了 XenDesktop 头上。
 
下面是二篇英文文章比较 PortICA 与 ICA 的差别。
 
Why ICA is not ICA
http://www.ervik.as/index.php/citrix-mainmenu/xendesktop/1248-why-ica-is-not-ica
 
【关键摘要】 What does this mean for XenDesktop? Well, of course the ICA stack in XenDesktop inherits heavily from XenApp (Jeff has blogged on this extensively, and Brian has a more detailed analysis too). But the underlying infrastructure is very different: XenApp builds on top of Terminal Services, while XenDesktop uses basic OS APIs. This means that some XenApp features that are intricately linked to the Terminal Services platform, like shadowing, are by no means a straight: "just recompile this for Windows Vista and it'll work". Instead, we had to re-code some features from scratch in a way that's different from, but compatible with XenApp. All this takes time, and that's the main reason we shipped the first version of XenDesktop with some of the "ICA features" missing.
 
PortICA: The same, but different
http://www.brianmadden.com/blogs/brianmadden/archive/2008/04/14/accessing-windows-xp-and-vista-via-citrix-xendesktop-ica-portica-how-does-this-really-work.aspx