I saw this complaint about iPhone volume and thought I would throw my two cents in on my biggest complaint about the iPhone as well.
My biggest complaint about the iPhone is that there is no way to filter junk mail. Mail works great on the iPhone almost exactly like it does on your desktop but there is no junk mail filter for iPhone.
You don’t realize how big a deal no junk mail filter is until you don’t have a junk mail filter. The volume of junk mail is unbelievable. Not having the ability to filter junk mail on my iPhone renders email on my iPhone virtually useless. I’m almost afraid to check my email on my iPhone because I can’t filter the junk. For me, that means on a single check of my email maybe once every two hours would bring me 30 junk mail messages and 5 legitimate emails. This just isn’t a viable ratio. It kills the whole idea of productivity to have to sift through the junk to get to the real stuff.
My limited understanding of the iPhone is that it runs OS X more or less just like a desktop. So why not filter? I have 8GB of space on the phone, I’m sure I wouldn’t even notice a filter space wise.
I hope a junk mail filter for iPhone is something that is on the way with the next iPhone software upgrade, but until then, I won’t be checking my email on my phone.