Think Jazz is a good album, but an 'alternative' album.
Anyway the vocals on If you can't beat them, I think are amazing. They're not challenging like say Bo Rap, but just hearing them on their own they sound so fresh and kind of how to sing well. Perfect singing. God why do people like Mick Jagger get all the attention, when people such as Freddie were the ones with the real talent - always get overlooked.
Commercial success and talent rarely are synonymous, especially these days.
Success in the mainstream is achieved when you have commercial appeal, and are providing something that your audience demands and wants (or thinks they want, via the media). A catchy song and connections within the business are all you need.
I love Jazz, but deem it their worst 70's album. It definitely transitioned their sound from the early days into their 80's sound. What I love about it is the diversity of their tracks, the experimental aspects of a few songs, and it really does show the value of Roy Thomas Baker, at least to me. It brought back a difficult to describe aspect that peaked with A Night at the Opera before dissappearing during the two albums they produced on their own. I deem If You Can't Beat 'Em, Bicycle Race, Dreamer's Ball, Dead on Time and Mustapha as some of their best.
The only negatives I have with Jazz is that it lacks a real Queen-Classic track like a Liar, Black/White Queen, Lap of the Gods, Bo Rhap, Prophet's Song, Millionare Waltz, Take My Breath Away, WWWRY/WATC, Spread Your Wings, etc... The best for me is probably Dead On Time, but no track touches the top 2 of any album previously released. I also think John and Roger dropped off considerably after their phenomenal contributions on News of the World.
I still say that Dreamer's Ball would have been a number one hit in the USA. Follow that up with Don't Stop Me know and it would have beaten The Game to number one on the album chart.