Metrics? Advanced features?
WKO5 for the win because of graphing, and control over the graphing.
That simple.
Extended-CP model (GoldenCheetah) and WKO model. They give very similar results (but not always).
Formal testing over learning how it feels? Gosh I dunno, IIRC you’ve debated with me about long testing. Formal tests like the ramp test are a joke for FTP estimates, its a MAP test. Its so tedious debating stuff like this. I’ve been doing long testing since spin classes. Go long, learn how it feels, don’t be lazy. No shortcuts.