I do like hearts timeline, where you do get a few different tunes to normal, but even then after a while the same songs crop up, they seem to have maybe 10 songs from each year to pick from.
Jason donavons 80s show is the worst, I've mentioned before that it's just the daytime playlist with 1 or 2 slightly rarer tunes played, while real radios high school days, that was on prior to this was a great winding down Sunday show, loads of rare 8os hits, one hit wonders, mixed in with a nice a bit of cheese.
Heat radio gets the variation the best I would say, with the newer tunes played, and not just, Sam smith, George Ezra, e.t.c , but blended in nicely with some 80s and 90s tunes with some rarer ones thrown in as well, especially on reheat.
It's all about opinions though and everybody has so many music tastes, I like most types of music, so I can be pretty versatile with the radio dial.