Maybe I'm in the minority now, but I still find UA miles immensely valuable for those of us whose main purpose of travel is to visit and enjoy as many destinations as possible around the world. I couldn't care less about "trying new product" when I fly. I'm not like some of the bloggers who spend most of their time flying or gushing over the upgraded suite, instead of getting to know the destination.
I hear gasps of horror...I know..shocking concept. I've discovered for myself that UA miles are way too valuable to waste on the excess of first class.
Some of the reasons are...
1. 10k mile bonus, so with $25k of manufactured spending at about $270 cost of GCs + MOs, I have myself 60k miles, enough for roundtrip to Europe or South America, with a free one-way left over.
2. Generous routing with two open-jaws and stopover, I can still do RTW trips that would cost close to $3k to buy, for 60-80k miles in coach.
3. Flexibility to change flights while the itinerary has started. Very useful for unexpected changes of plans due to weather, illness, etc..
For the occasional treat, I can always book biz or first using the much less flexible/valuable US miles or do an AA distance award.