custom builds are clearly the better choice for anyone buying a computer. dell and others sell computers because of heavy marketing that targets consumers who do not know enough about consumers to realize that they are being ripped off.
so when you pay $400 for a new dell tower just over half of that sum actually goes towards the parts, because dell has to pay for advertising, the salesman that sold you it, his manager, and so on. the only reason they are able to do it is because they cut as many corners as possible and go for cheaper lower quality parts.
when you buy a new $400 custom build from a local shop or technician, a way smaller percent of that money is eaten up by company overhead, so more of your money actually goes into what you paid for - the tower itself.
and perhaps most overlooked is the fact that a custom PC can be easily be maintenenced and/or upgraded by anyone in the world because its parts conform to industry standards. with a dell, often times thier specialized designsmean that the only place you can get parts is from dell. and they know this and charge as much as they want.
any way you cut it, a standard PC is better any day of the week
and further to that note, it should be known here that all the major OEM companies get most of thier business from businesses and corporations, all of which do not have access to fast means for getting standard PCs instead.