That may be true, but I have definitely heard more stories about folks having trouble upgrading components in Dell machines. CPU cooling systems bolted down and not allowing room or mount options for off-the-shelf coolers, ATX-looking connectors with swapped pins (problem for both PSU and Mobo upgrades), etc. Could also be that Dell is one of the more popular and affordable pre-built computers and all prebuilts suffer from this from time to time, though. Maybe we just hear more about it with Dell because that's what people have? ::shrug::
Just seems like Gateway isn't in the business of creating proprietary parts as much as Dell is, just judging by my un-scientific research. Maybe its just because they were bought by Acer, so I'm picturing all Acer standard components inside... dunno.