I don't have a scale yet... so I haven't weighed it (it's on the list after I finish moving and start my new job).
Mine is a large model, so it's a little bit heavier than 18 oz, but it's still surprisingly light. I've had it in chilly weather, but not quite freezing; it's kept me warm as long as I didn't let a draft in. I'm probably going to get a slightly wider one at some point (another "after I start working" item). I didn't cinch it up snugly though, which might have prevented the drafts when I rolled over at night. The 30 degree rating might be a little conservative, but I think the recommended temperatures that Ron has on the Spirit page are pretty close -- when I was out in autumn with my Spirit (it was cold enough for me to put on my down jacket while I was eating dinner), I wore only base layers when I climbed into bed. I kept extra layers close by in case I needed them, but the only time I felt cold is when I let a blast of cold air under the quilt. I guess I could have prevented that by snugging it up around me rather than running the straps under the pad. I haven't tried that yet.
I did get the eVent option on mine. I can't say how much of a difference it made, but I can say that I've been quite happy with that quilt, it's likely to be my choice for non-winter use. That's what the Blackwelder was for :)