I've never been to Boone, so I can't really compare them. However, here's my take on Greensboro. I live in Greensboro, like maybe a mile from downtown (totally walkable in the warmer weather). I'm an engineer, and moved here for a job, got laid off ofter a couple of years, and found another job within a month. I bought a house here too I like it so much haha.
Crime - Greensboro's like any other city - you have your good areas and your bad areas. And you probably have no reason to be in the bad areas, so unless you're looking for trouble, you'll probably be fine. I've never felt unsafe in the city, and I'm downtown all the time and late at night.
Why I like it - several reasons. number one is the breweries opening. It's not Asheville, but we have like three breweries in Greensboro (no, I'm not counting Foothills in Winston, nor Red Oak), and we have another opening in the summer, and another opening next year. I love local brews, so that's a big deal for me. Second, it's almost like you have pockets of different neighborhoods, with their own vibe - you got downtown, that strip up on battleground (with buckhead/1618/speakeasy), lindly park, westerwood, college hill, etc. So there's different places you can go depending on what crowds you like, or mood you're in that night. Third, I feel like it's a good size for someone who want's to have an impact on their city - a smaller city wouldn't have the resources for an individual to make an impact, or to implement their ideas. A bigger city, and the individual gets overwhelmed, like no matter what you do, no one's going to notice. Here there's a thriving young professional community, and if you have an idea that would make the city better, the resources are totally there to help you. Or if you just want to get involved in the community, you can do that.
As far as outdoors stuff - we have a ton of pretty big parks, and the ever growing green way. Also, we're close enough to the mountains - I did a day trip last weekend to go skiing. And I think it's like ~2 hours from boone, so not that far.
I have to disagree with /u/Garignak (is that a Galaxy Quest reference btw?) about the triad. I don't think you can lump them in together. At least as far as socially. Maybe professionally. I mean, I live in GSO, but work in Winston. But I can count on one hand the number of times I've left GSO to go hang out in Winston. And never have I ever hung out in High point. This is my honest opinion of the triad cities: Obviously GSO is the best because I live here. but I like it the best because it's a younger crowd, and the city is growing, up-and-coming, and still malleable to those who want to help mould it. The people who live here don't take themselves too seriously, and are down for a good time. Winston Salem is old money, established, for the stuffy, golf club, collar popping crowd. It got to where it is a long time ago, they like they way they are, and it's not changing. Sure their downtown has changed a little, but their downtown is like three bars. High Point used to be bigger, i guess, but I think some changes in the furniture industry have really killed it. Like I said, I've never been there to hang out, and when you drive through during the day it's like a ghost town. They've been trying to draw people to live there, but honestly, I just don't think there's the population to support a third city the size of Greensboro and Winston. Kernersville - I wouldn't live here either. I don't know if they even have a downtown, i feel like the only people who live there are families that have one parent working in GSO, and the other working in Winston, or people who are just looking for really cheap housing, and have no want for a social life.
Anyway, you guys should come down out of the hills and visit! like I said, it's only a couple hours away.