They haven't officially opened Southeast Blvd yet (I think they need finish a couple islands and put up new signage), but it's totally ridable from a biking perspective now. I've ridden up it all the way to 29th a couple times in the last week or so, but hadn't gone the other direction yet. This morning I decided to ride it from top to bottom on my way to work and see how it went.
The ride from 29th to Perry was predictably busy, but not too bad. The bike lane starts up again around 28th and continues down from there until you cross the freeway so it's probably one of the longest continuous bike lanes in Spokane. I ran into construction signs planted squarely in the middle of the bike lane right before the Perry intersection so I had to rejoin traffic, but it wasn't a big deal. The right lane beyond Perry was still blocked by road closed signs so I needed to go around those anyway.
Once I got beyond Perry it was fresh pavement, virtually no traffic and a clear bike lane all the way down the remainder of the hill. There's still some street parking on Southeast now, but it's all on the uphill side so there's no danger of getting doored as you cruise down the hill. I did have to avoid a truck parked squarely in the middle of the bike lane near the beginning of Sherman, but it wasn't really a surprise. On past rides up the hill, I've noticed that truck and a few other cars in that area haven't fully accepted the new layout of things. Perhaps once some Bike Lane/No Parking signs go up they'll get out of denial and take advantage of the plentiful parking across the street.
All in all as a bike commuter I'm really happy with the way that Southeast Blvd turned out. The execution of the bike lanes is about as good as I've seen in Spokane to date. Once it's officially reopened I think it will probably be the most bike commuter newbie friendly way up and down the South Hill.