There's not one answer to that question, kinda like asking what's the best vehicle, it really depends on what you're going to use it for.
If I'm looking for a handheld VHF/UHF radio, I want it to be small (but not too small), cover at least the two main bands (2/70), have good battery life, accessories that interest me (that are priced right), features I'm interested in, good price, and available when I want it.
If I'm looking for a mobile VHF/UHF radio, I want it to be fair sized, reasonable power levels, easily mounted where it's convenient for me and out of the way, accessories that interest me (that are priced right), features I'm interested in, easily operated while driving (don't want to look at the radio, I want to watch the road!), good price, and available when I want it.
If I'm looking for a mobile HF radio, I want it to be fair sized, reasonable power levels, reasonable power draw, easily mounted/removed (but still secure), accessories that interest me (that are priced right), features I'm interested in, easily operated, good price, and available when I want it.
If I'm looking for a base HF radio, I want it to fit my desk well, easily accessable controls (with a button to lock them down so little fingers don't change things on me when I'm not looking), good sound (both receive and transmit), accessories that interest me (and are priced right), features I'm interested in, good price, and available when I want it or fairly soon afterwards (I'll wait for a good model).
Generally I don't like the "all in one" radios. If my HF base covered DC to daylight, I'll probably just use it for HF and use my dual-band for VHF/UHF for those bands. If two radios tie for my appeal and one is HF only and the other full coverage I may go for full coverage, but only if the cost difference is quite small.
I seam to generally like one brand's radios, but will happily get one of the other brands if the price & features are right. I generally don't like features that are added just to make the checklist look full, but are pretty much worthless to me. I actually may subtract points for them when doing my comparison. I also feel it's important to "play" with my final few prior to making my selection (either at a ham store, if available or at a local hamfest). Reviews are nice, but unless I know the reviewer, I don't trust them 100% ("know" may be from having read their earlier reviews and agreed with what was said, both good & bad) although visiting a ham that regularly uses that radio and having them show me around (and then letting me "play") is always the best option.