UA Silver Experiences/Comments
As a general response to the OP's post, I think the overall take away should be that it's very subjective and it depends on many variables (home airport, routes flown, times, & what's you value in terms of benefits).
I think the best and most valuable benefits for a Silver are improved IRROPS handling, improved customer service, E+ and premier access security lanes. The upgrades are nice when they come, but don't expect them and you'll be much happier.
Don't let the GS' and 1K's of the world downplay the benefits of being a Silver. Obviously a GS or a 1K is going to have it better, but that's the way it should be. It doesn't take away from the added benefits of being a Silver, especially over a GM.