Imsey Vimsey trainers are nice and trim but they need to be changed immediately or they'll leak, that was our experience. LOVED them for day time because they fit so well under clothes but I couldn't use them for night.
For night we used Mother Ease diapers (mother-ease.com). I used the Large Sandy's diaper, which pulls on and off, but has snaps. Their Air Flow snap covers are made the same way and come in cute prints. I've also used the cheaper Tiny Tush brand pull on covers, which are just plain white but so much cheaper than the Air Flows. (Tinytush.com) The Sandy's are not trim like the Imsey Vimseys, but better than Happy Heiny's pocket trainers in my experience. They are very absorbent and I was very satisfied, because I needed that absorbency. And DS never seemed to mind. Mother-ease also makes different diapers, trainers, and bed wetter pants but I haven't tried them.