[vbezhenar]

I bought Dell 3410 once which was shipped with Ubuntu. I closely inspected that Ubuntu, compared it with vanilla Ubuntu install. All I've found are branding packages (desktop pictures, etc) and one package which blacklisted some module. No secret drivers, no secret kernels.

Can't comment about XPS, but I feel that it'll be the same.

[freeqaz]

Dell does the work to upstream the hardware support into the kernel. It's pretty rad. I miss my old XPS 13!