I have both an open and a closed toe.
I like the open toe for visibility BUT the front edges of the foot occasionally catch my basting threads (I baste with water soluble thread so I don't have to remove the stitches). I try to watch and hold them down until I get at least one stitch on them, but sometimes they catch. If I don't notice right away and they pull too far it can mess with my FMQ design ARGH!!
The closed toe will also sometimes catch on my basting threads bu it's easier to notice.
All in all ... I prefer the open toe.
Mine is a clear plastic toe.