Yeah, it is true that their ability to update is somewhat limited based on some of their proprietary components in certain models.
Oddly, though, I'm given to understand that their power supplies might be a bit more robust than their generic appearance and modest power ratings indicate.
That all said, I am still running on an Haswell XPS 8700. This is my main PC. Over time I:
- Put in an R9 285 (when I bought the Dell)
- Upgraded to 16GB of RAM
- Added a pair of 500GB SSDs
- New PSU (Seasonic, 650W) - with the intent to get a 1080Ti
- GTX 1080 FE
Had I known I'd wind up with a 1080 instead of a 1080Ti, I likely would've stuck with the factory PSU.
My son's XPS 8910 wound up getting the R9 285, added a 500GB SSD, and recently upgraded to an RX 580 8GB. Going to increase his RAM to 16GB from its current 8GB as well.
For the most common upgrades, they're quite doable, and have been reliable. At his mother's house, he's using an old Sandy Bridge XPS 8300, with a GTX 660Ti+ (EVGA 3GB model) swapped in.
Some of their layout choices and proprietary bits are irksome, but they've been very reliable, and handle gaming and such pretty darn well.
I do keep telling myself I'm going to build my own "next time" . . but when I get to that point, it's like they know, and have some kind of crazy sale.