I find Mobile Office quite useful, a few weeks my last job contract ended and I had my Resume on my phone. I was able to make quick edits when needed and sent it out to interviewers.
The OneNote is also nice to make quick notes that you can access from your phone or your windows live account.
As for the lack of carriers, they're coming to Verizon later this year.
" lagging in features "multitasking, cut and paste, and custom ring tones." most of this stuff will be there by march. Plus I can multitask with the phone right now, just not with 3-rd party apps. I can still listen to music, while texting, or writing email or surfing the web. I can't imagine what other multitasking i need. As for copy paste, I've only seen a use for it very few times. Custom Ringtones is also not a big deal, but would be nice.
". Small library of applications." Well yeah.. it just came out. It's growing fast for the time it's been out.
"Thing is people are pretending that this is Microsoft's first OS in the Mobile space. It isn't called WP7 for nothing folks." This may not be their first phone, but they rewrote the OS.