The bursitis flare-up was quite painful. It caused weakness as well. It was uncomfortable at the top third of the bench, and even when squatting (due to the weight of the loaded bar pressing on the shoulder).
Once the majority of the flare-up had subsided, I was pleasantly surprised to find that I could use a Hammer Strength bench press machine without any pain. Seeing this to be the case, I figured the same would probably be true of the Smith. Fortunately, it was.
Much has been written about problems with the Smith. In my personal observations, there are definitely problems with it. The main one is the forced groove. I lift straight up-and-down, as I mentioned, so that's fine for me. For others, I think that would make the Smith a terrible option. It's hard to learn the straight-line groove technique and I don't think it can be learned on a Smith, so I think that takes out most typical commercial gym lifters.
So, I still believe the Smith machine bench is a bad option for most lifters. I may be one of a lucky few who happens to fit the odd constraints of the device, so lucky me, I guess.
I can press while waiting on my shoulder to recover fully. I guess anyone else with a Dave Tate-style lift could probably use it for some stuff (rehab, etc.)