nojackets
Personally I would choose on reliability and safety.
I don't think there is much to differentiate carriers here. Pretty much all are incredibly safe, and reliability is much the same too. I can think of a few 'unreliable' carriers, but the ones I have in mind don't fly long haul where the upgrade really counts.
Do some of you actually base your decision about who to fly with
Yep, I do. To be honest, it doesn't make a vast difference, but some airlines/alliances are better than others. Put all your miles in one account and get top tier status. There are other significant benefits, like lounge access, check-in without the queues, better seats in economy if you don't get an upgrade, upgrade certificates, etc etc etc.
I don't think the 'MacDonalds' and 'Tesco' analogies hold water. These businesses have never held out the expectation of upgrades by providing them, the airlines have. The airlines only have themselves to blame for this. For instance, airlines deliberately overbook their economy seats so either have to pay compensation or upgrade. As people know they sometimes upgrade because it's cheaper, you cannot criticise them in the slightest for trying to increase their chance of receiving that upgrade by the harmless action of asking for it.
If Tesco started giving extra ham to those who asked for it, you can bet your bottom dollar that people will start asking. If you want to find fault with this, don't point your finger at the customer
