Yeah, I'm nt exactly saying Dells are bad in the complete sense of the word. At least, I don't mean it to come out that way.
Its just, if you prefer to choose whats in the computer, you don't have a choice, and if you want to upgrade, you also don't really have a choice (though maybe some small things can be)
But yeah, its fine for a user that wants to buy a PC, play to there hearts content doing buisness work, or games of course, but will know that after about a year or so, the computer will be out of date and will start to look old to them, and they can't really do anything about it without spending alot of money.
Also, a pre-built machine would be fine for someone that didn't care, as it'd probably last them a long time (Maybe 5 years or something) doing what they want to do on it, as long as its not high running games.
If you put it in the 5 year terms, its a very good deal, but most wouldn't want to keep it running for that long with what it had originally.
To update, you'd end up having to change the motherboard and probably the entire PC to get it up to scratch again, so its like your modding your own system by the end of it anyway, so you could build one and save you the trouble