I also got the bobike mini and love it, again same problem as JeffS in that I had to attach it to my wifes bike as the stem on my MTB was too big. Still, I've got an old cruiser style bike I want to attach it to for summer.
The seat is great and my 17 month old son loves going for rides in it. We got it when he was about 14 months old and we've only done short trips in it because it's been cold, we generally go to the park or to see the horses in the fields down the road.
We don't have the windshield, but maybe we should, I'll look into it.