If you're a lazy sod and can't be bothered then Which is pretty good.
Their recommendations are usually OK, might not be ideal for your use case but you won't have gone far wrong.
I suspect e-bikes are like normal bikes for a lot of folk, they do a handful of miles here and there and the Which report is based around that.
I bought a Bafang, cheap and Chinese.
I bought it because there are many thousands being hammered out there, it's probably one of the most tested motors on the planet - and definitely one of the most abused.
Loads of people using them to do high mileages, the spares are cheap as chips and there are several YouTube vids for every operation on one you can think of.
Ideal for my high mileage commuting and easy enough to repair and get on the road in a couple of days should the worst happen. (Which over 25,000 miles it never did).
Even better it allowed me to take my favourite bike and electrify that.
The point being, Which could never have found my ideal ebike simply because I already owned the main part.
Is the Bosch better? Probably, but just not for me.