I've read and heard a lot of bad things about both Gateway and Dell. I'd suggest for you to google reviews on Gateway, there are many good sites out there that do consumer ratings on products and companies and since they are consumer reviews you can get a more objective opinion on a product rather than a site that is selling or promoting, consumer reviews aren't trying to sell you anything.
http://www.epinions.com/
http://www.ratings.net/
Mooseburger posted a good link, another one is
http://www.ncix.com/
Based out of Vancouver, I have bought parts from them to build our home pc's and know many other tech guys that order from there. They sell parts or you can have a custom built for you using common parts, they have great customer service too.
I've read that Gateway often use substandard parts, I know a few years ago there was a huge issue about this in the PC world. If you live in a big city there is often quite a few places that will custom build a great PC for you for your needs. Plus all the brand stores out there like Future shop, Best Buy etc that sell off the shelf pc's that at least have localized service areas.