I've paid a lot of my own money to upgrade business trips in the last few years.
When I tot up how much each year, it makes me wonder if I'd have done better spending the money elsewhere.
I like WT+ (old and new!) and can sleep reasonably well there. Of course I'd prefer to be in CW but by the time I'm out of the airport I honestly don't think CW over WT+ makes any difference at all to my mental or physical well-being.
You can get good or bad food/neighbours/crew/flights in any class of travel. It's particularly galling to opt to shell out a chunk your own money to upgrade and have a crappy time for whatever reason.
I don't think I'm going to be quite so flash with the cash this year. Let's see how that goes for a while.