I don't think there's an obvious answer to which tablet provides more value - it's very context-specific.
In the same way, if someone wants a top of the line tablet, it just seems obvious it's an iPad. That's what almost anyone with a tablet is going to have. It's just going to fit the expectation of what a tablet is for a naive user. Surface doesn't. Just like Linux on a desktop may be better in your context-specific suggestion, but it isn't what a naive user thinks a computer is.
Unless the friend also wants to pay me regularly to teach or tech support their computing device, in which case I might go outside the expected zone, but I've yet to find this to be the case.