Yeah, I usually use Epocrates as well. However, U2D Mobile is an app, and so is basically instant search and display. When you use U2D over a wireless link to a web site, as well as eating your battery, you are dealing with WiFi latency and TCP transmission delays (it's a 3-way handshake to get a single data object from any website, and a webpage is made up of many objects). Plus, you may have anywhere from 5-15 hops between your handheld and the U2D website. All this adds up to a sluggish response. If you have a device with a real, tactile keyboard (for surreptitious data entry by feel) and speech-to-text search, then you'd be surprised how quickly you can call up data. If you are doing Surgery rounds it's probably not going to help you, but if you are rounding on a tricky Peds or Medicine case then, when everyone else has chimed in, you are usually ready via U2D to describe some of the edge cases it could be, or to specify the sensitivity/specificity or PPV/NPV of a particular test/scan. Basically, it's a combination of a fast app, good furtive input that doesn't depend exclusively on peering at a screen, fast reading, and knowing how to navigate U2D Mobile's headings, then you are set.
Well, a 16GB memory card was just $12 yesterday on Fatwallet, and the 32 GB cards are dropping like a stone. So 2 GB really isn't that big a deal.
And as for interface, that's a matter of opinion. I wonder if you've tried Android or WM with SenseUI, which is all full of the same kind of finger swooshing, pinching, etc. And often with them you have glass screens with haptic feedback so you get a literal feel for what you are doing. Or the Palm Pre, with the WebOS, actually designed by all the people who created the iPod and iPhone at Apple... basically, it's iPhone Interface Version 2 ("improved"). In any case, for medical apps the individual interface is key. What is "superior" on one platform may suck on another. Epocrates on Apple, is kind of borked compared to some of the other platforms. And the (current) lack of multitasking on iPhone means you can't easily switch between medical apps, say to check a DICOM and compare it to a Google/emedicine/U2D image. That's just a single example where the modal iPhone interface restricts your workflow.