i was in americorps state, which is more similar to the peacecorps as i understand it.
how i mean that is, it lives up to its 'domestic peacecorps' label: we were performing street outreach in detroit, so it was directly working with the destitute in a region that experiences marked struggling.
many of the folks i served with were vistas. vistas work behind the scenes in a more programmatic way. you are not going to find them on the front lines. if they are doing outreach, it is bound to be educational. so, being a vista would not give you that direct service.
however, if you are in a well funded americorps group, you will get to do service projects every week outside of your placement. i planted a lot of trees, washed a lot of walls, swept a lot of floors, cleaned a lot of dishes and warehouses and whatnot. if i sound excited about that, its because i considered it to be the best part of my service. the manual labor as part of a group was so mentally healing. and about the 'group' that i was a part of. it seems that americorps (i met memebers from all across out state) draws folks who are kind of hipsters. that or they are very smart people who havent found their professional place in society. so, if they are educated they are still likely to be awkward. i also thought they were humble for the most part. they are a struggling bunch of folks, which i thought made them way easy to be around. you dont have to 'try' to be friends with anyone, you know? it just happens because you're both painting the same fence. its strange and its good.
im glad you are thinking about vista. nccc seems way cool too. i would not recommend state or national because of the direct nature of the service. the direct service (which i am still doing by the way, but as a staff memeber) has put me in the hospital for what i believe to be stress overload. the day to day is never easy either. you may get the same benefits from vista that you would in direct service programs. speaking as a weird guy who doesnt do well in social situations and has trouble making friends, that aspect of the program was a blessing to me.
sorry i rambled. you can pm me if you would like me to say anything else?