Having knitted my first top down sweater on circular needles a couple of years ago I've become rather partial to seamless knitting. Sewing up knitting is something I really don't like doing and find hard to do neatly. I've knitted a couple of things since from flat patterns (bottom up) but have done the fronts and backs as one piece and the sleeves with circulars on one of them too.
I came across this website
Olive Knits and discovered that she is a big fan of seamless knitting. I quite like some of the patterns. I like the short sleeved cardigan with the curved fronts but I do have something in the pipeline for when I finish the cardigan I'm currently knitting so won't be trying it just yet.