The general issue that we've been hearing about is that tasks that get sent to the background on the HTC One X are not being held in memory, but rather are being shut down, and so when you go back to an app it will start from scratch, or in the case of the browser, it will reload the page you had open no matter what. This effectively made multitasking non-existent aside from the HTC-built apps, which are actually held in memory.
HTC commented on the issue today, and effectively said that it made the memory management and task killing on the One X extremely aggressive on purpose. Of course, HTC started out by placating users, but that probably won't go too far. The company told The Verge:
So, there you have it. Killing your apps is considered "normal" by HTC's standards. Just so everyone understands what the issue is, here's a video made by a reader of the multitasking on the One X.