So the question in the thread title is necessarily a subjective one (leaving aside the question of whether "fastest" = "best"). However we do have some objective data to try to make an assessment. Although cars' performance varies we do have team mate comparisons to draw on, and qualifying times are a 'cleaner' data set than race results given the number of variables involved in a Grand Prix. So, with apologies and thanks to Rutherford, I've analysed the relative performances of team mates in qualifying sessions for the past decade and more, the results of which are shown below. The basis of measurement is a percentage, representing the average gap between the faster and slower driver(s) over the course of a season. To save decimal places and for easier interpretation, I've scaled them up by a factor of 10,000. So in the chart below, +1 means a difference of +0.01%, and +100 means a difference of +1%. Over a typical lap time of 1m40s, +1 = +0.01% = +0.010s compared to the faster team mate. In this case, +10 would be a difference of one tenth, and +100 would be a difference of one second and so on. The comparisons all exclude wet sessions and those in which drivers have had mechanical problems - as far as possible from contemporary reports. Then I have tried to create a basic model of driver speed from this data. One of the problems with this approach is that occasionally there are situations where A > B > C > A. A classic one is when Damon Hill beat Jacques Villeneuve in 1996 (+43), who beat Heinz-Harald Frentzen in 1997 (+43) and 1998 (+21), who beat Damon Hill in 1999 (+61). I would argue that there are two effects at play here: a rookie effect (disadvantaging Jacques in 1996) and an age effect (Damon was 38 in 1999) that explain the apparent anomaly: Villeneuve got faster over the period while Hill got slower. Analysis of the past decade seems to suggest most drivers gain speed from their first into their second season. A minority appear to improve further in the third season. This seems to be independent of the age they make their debuts. Additionally, some drivers show signs of losing pace from the age of around 33 onwards - although this isn't consistent or true for everyone. So I've taken a simple model that assumes a driver's speed is constant, except in their rookie season (or two), and assumes they decline gradually from age 33. Then using the historic team mate comparisons, create an estimate of their speed over the course of their career. I've chosen Hamilton as my baseline, driver 0, on the basis that he's a qualifying expert and has had some long-term team mate relationships providing a good sample of data. So from Hamilton we can get estimates for Button, Rosberg and Bottas; from Button on to Alonso, from Alonso on to Raikkonen and so on. This is what I came out with for the 2017 grid, plus Button and Rosberg included for reference: As you'd expect there are a few adjustments where the model didn't quite fit. It made sense to assume Raikkonen wasn't the same driver after his two year break, given the wide margin between him and Alonso and, latterly, Vettel. I assumed Massa took some time to recover from his 2009 accident, while I've chosen to represent Kvyat declining after 2015 - although you could take an average of his deficit to Ricciardo across those seasons, which would move him and Sainz up a bit in 2017. Finally the only driver who I couldn't fit to the model at all was Magnussen. He was marginally faster than Button in his rookie year of 2014 (shown on the chart) but has been very underwhelming against Palmer and Grosjean since. I've put him at +88 since it's easier to assume one season was the outlier rather than 2016-17.