XLR to USB converter for Mac

I'm looking for an XLR to USB converter for Mac. So far, these are the few options I'm looking at:

• Shure X2U XLR-to-USB Signal Adapter
• Blue Microphones Icicle XLR to USB Mic Converter/Mic Preamp

If anyone has any experience using any of these, share your thoughts in the comments.

UPDATE: Found this one also: the Zoom ZH4N Handy Portable Digital Recorder. It's an audio recorder that also works as an audio USB interface. It has it's own mic, plus a few ports (including XLR ones) for external mics. I'm just not sure if, when used as a USB interface, you can only record from the primary mic, or if it lets you record from any external mic directly to your Mac.