I am using WP 2.7 and really like it. I upgraded from 2.6 and the upgrade seemed to go well. The only glitch I am having is that now when I uplaod and image I cannot select the size, for example I cannot choose thumbnails or medium or large image preset sizes. It is set on full size and I cannot change it.
I use the Browser Uploader as the Flash Uploader will not function. I had the same problem with WP 2.6.
I suppose I can uplaod the image full size then reduce it manually but I just wonder if any one else has had this issue and resolved it.