Great product that yielded great results.  To ensure the best possible results, I started by drawing a level line approximately 4-1/8" from the ceiling and worked down.  This ensured a clean abutment to the ceiling and allowed me to hide any imperfection behind the baseboard at the bottom of the wall.  It worked great.  An 11' wall took about 4 hours all-in.  I highly recommend using a vinyl tile cutter ($30 any home store) to make the job easier and your seems seemless.