My personal experinece with Compaq has been if it is a Presario - it is very bad....period. As for the rest of the Compaq lines, they are fairly decent, except they insert a ROM chip of some sort in one of the memory slots (usually only 2 slots in a machine - efectively giving you one slot for memory) and the computer will not boot without this chip. Also, I have upgraded 5 different Deskpros (2-667's and 2-600's, 1-933) from NT 4.0 to 98se. I haven't had any major problems, yet each one has had problems.
The biggest problem on the 4 smaller ones was an unidentified device. It always popped into system properties as "Other". Even after contacting support = no help, because it was designed for a NT restore disk, and sweet talking one of the tech receptionists into sending me a homemade (burned) CD of drivers, I still couldn't get the device to identify. I think it has something to do with the on-board audio.
The other minor problems all of them experience is after a screensaver kicks off, there is a program box on the task bar. It usually is empty, but sometimes says screensaver. After the screen saver kicks on and off 5 or 6 times, the task bar fills up. Clicking each one makes it dissapear, but it is a nusiance none-the-less.
One further note on the presario line, if you ever call their tech support, even Compaq knows the pressario's are junk, it is evident in their automated menu choices..."For pressario products, press 1, for all other Compaq products press 2"... That is a pretty broad range encompasing scanners, iPaq, scanners, monitors and several other computer lines (including desktops, laptops, servers and handhelds). The Deskpro support group won't even interact with the pressario support - it is two seperate divisions in the company....and the products are worlds apart.
One word of advice is check all of the drivers before uninstalling the original OS and you can usually find everything you need online under their driver sections. Sometimes you have to look at different machines then what you have, but you can find the appropriate speed machine with the proper OS you are upgrading to.