First of all, a declaration of bias. And not just a little red-tinted-spectacle bias but "a deep, pure and heartfelt love for Patrice Evra" bias. A "who is better, the player who has made it his business to embody the spirit of the club you love, to be the fans' representative on the pitch, to wear his United-loving heart on his sleeve, or some guy who plays for Everton?" bias.
My answer to this question will always be Evra, but, in truth, I would stop and think for a minute before answering the question "Who is better, Patrice Evra or Lionel Messi?" I mean, I would say Messi, I'm not certifiable, but what I'm saying is, I love Evra so much, I'd think about it.
With that out of the way, here is a completely impartial look at the two left-backs.
There are three years separating the births of the two players, with the Frenchman being 32 and Baines 29. Baines joined Everton the season after Evra joined United.
Since then, Evra has won five Premier League titles, three Football League Cups, a Champions League and the Club World Cup. Baines has finished runner-up in the FA cup.
On the other hand, Baines has shone in the less successful side, winning Everton's Player's Player of the Season three times and Everton Player of the Season twice. Evra's only domestic individual honour has been his inclusion in the FIFA Fifpro World XI in 2009.
That Evra has spent his career at the highest level of club football, making a vital contribution to the side that reached three Champions League finals and amassing an impressive collection of silverware, whilst Baines has been the standout player in an upper-mid-table Premier League side would suggest that—over the course of their careers as a whole—there is not too much doubt as to who the better player is.
Evra has more than twice as many international caps as Baines: 54 to 22. Whilst this is not a definitive metric, given that so much depends on the quality of other players in the same position of the same nationalities as the two men, it is notable that Evra has kept his place in the France side in spite of a history of controversy.
However, whatever the relative successes of their careers, and even if you accept the premise that this indicates Evra's superiority in past years, there is certainly a case to be made that Baines has now surpassed the Frenchman.
Per Whoscored.com, Baines has better numbers in each of the attacking statistics measured. That means he has made more key passes, taken more shots, made more successful dribbles, been fouled more often and has been dispossessed less often than Evra.
Defensively, the statistics are a mixed bag. Evra has made more clearances (by a long way) and more interceptions, but both of those statistics may be influenced by the relative styles of play of their teams.
Baines makes a good deal more tackles per game, commits fewer fouls, is dribbled past less often and blocks more shots.
There is no statistical measure for "number of times fans of his club have shouted 'for goodness sake, man, get yourself back into your own half, they're attacking now' after losing possession," but if there was, it is hard to imagine Evra losing out to anyone.
Unfortunately, time appears to be catching up with him, and his swashbuckling style has left United exposed on several occasions this season.
Reluctantly, given that Baines is at his peak and Evra is past his, the only conclusion that seems fair is that most people, asked to select one or other of the men for their hypothetical teams, would select Baines.
However, if they were asked to say who has been the better player over the past decade? That is a debate that could run and run.