Pepsi has improved

[AirbusA321]

Please check my sentences, especially if the usage of "yet", "still" and "though" is correct and if there are differences in meaning.

1a Pepsi has improved its taste, yet I think that Coca Cola tastes better.
1b Pepsi has improved its taste but Coca Cola still is yummier in my opinion.
1c Pepsi has improved its taste, though Coca Cola is still the better choice.

2a He has no college degree but still keeps on having success in the business world.
2b He doesn't even have a college degree, yet he keeps on having success in the business world.
2c Though not having a college degree, he keeps on having success in the business world.

 

[probus]

In AmE I think that "but" is usually preferred over "yet". But there are many dialects and I have often heard "yet".

 

[Lynxear]

They are all correct for me. However it is not possible to decide if there is a change of meaning since every sentence is different.