Not according to the GPU thread in the UA forum (that's a bit of a joke). Haters gonna hate, and people who are flexible with their schedule will have 80% success on eUps as E35K.

Although it should be noted that you can only upgrade your W fare because you credited 100k miles to UA. If you were a lower level, you wouldn't have any GPUs. AC at least gives you the (overpriced) option to upgrade as a lower level. A lot of people seem to use the W fare upgrade-at-booking example as why UA is better than the new co-pays, but it really isn't.

Both airlines have their advantages and disadvantages, both can suck, but both can be great.