I forgot to mention that there are benefits to both the 31140 and 31150. The 31140 was initially meant to be the cheaper stripped alternative to the 31150/BU1017/BU1018. The 31150 has a more powerful motor, a longer cord, one more height adjustment, a dirt sensor, and so forth. On the other hand, the 31140 is still as or more powerful than most vacuum cleaners and the brush roll is way easier to remove and far cheaper to replace. Either one does the job, though. The 31150 was actually so powerful that they had to put extra gaps at the front of the baseplate, which do help with larger debris pickup on hard floors. Both the 31140 and the 31150 take the same bags and filters.