I am surprised how people easily say that they get zero value from GUFs. Speaking for myself for the only GUF2 i ever got and managed to succesfully redeem a few days ago i think the overall value i earned is superb!
2 x First class, LHR-HND. Combined with an AMEX 241 cv. 180k avios and £699 x 2 in taxes. Cash price currently at £18132.

Assuming that each avios has a value of 1p then £1600 per person (avios & taxes) for a trip in F is once in a lifetime bargain for me.