I am a part time bike commuter (average 3 days a week in the spring-fall, not much of a winter commuter). My ride is 8-9 miles each way, depending on the route I take. It consists of about 2 miles of gradual uphill, two miles of relative flat, and about 3 miles of downhill (then flat as I cross into town from the North Side.) Door to desk, it takes me about 50 minutes, which includes securing my bike at the Bike Center on 7th, a really quick change of clothes and a three block walk to the office. The bus is usually less than 10 minutes faster (they get an express route for half the trip). My most frustrating area is through the North Shore and into town. Lots of zig zagging means lots of lights.
I have access to a shower at a Y (at which I am a member) less than a block from my office. I have NEVER used it to clean up between dropping off my bike and entering my office. An air dry and a quick swipe with baby wipes works well for me.
I don't know that I will ever be a full time bike commuter. The nature of my job (night meetings, etc) and my other obligations (volunteer work, classes in the North Hills, etc) mean that there are some days when I just can't do it. And, I don't like riding home alone, at night. As I've mentioned here previously, the Chateau Trail creeps me out, so I usually take a road route through the North Side, into Brighton Heights, and then into Bellevue and beyond. I've never had a bad interaction, but I sometimes FEEL like a potential target because I am alone, and because I ride REALLY slowly -- especially up hills.
The biggest improvement in bike commuting for me has been the Bike Center on 7th Street. No more worrying about my bike while in the office, etc. Well worth the $100 annual lease fee, at least for me. But, I miss my old "friends" in the portico of the garage on Sixth and Smithfield. That's my other "go to" place for bike parking downtown.
Before moving to Pittsburgh I was a virtual full time bike commuter in Wisconsin. At least if the roads were clear. But, that was in my younger days. Much younger....!