No USB Mass Storage support on the Galaxy Nexus. Well, for us Linux (and Mac) users that's some bad news.
BTW, MTP has great advantages from an engineering PoV: you don't have to use a crappy FAT filesystem on your eMMC. You don't have to give full control over an essential piece of storage to another OS, so you can continue accessing data/apps installed on the storage.
This issue has turned the phone from must-have to never-want for me - it's unbelievably handy to essentially have a 32GB USB hard disk in my pocket wherever I go. Are there any actual advantages to MTP or PTP for end users?
MTP allows the storage to be accessed by the phone and computer at the same time.