Initially, I would buy W fares. Now, after hanging around FT for a few years, I only buy Y/B fares - to increase chances of my SWU's clearing and to maximise EQM's. I am fortunate that my travel is client funded, so it's not coming from my pocket directly.

I've got a trip next month to NRT/TPE and HKG (from SIN). UA is definitely not the easiest way to get to all 3 - but it is doable. I priced it all in Y and that's what I intend to purchase. Not interested in playing upgrade lottery anymore and will use EF heavily to plan travel accordingly - for long-hauls, will now only buy Z/C/D etc