It's also praised in the current
Sight & Sound - which doesn't do star ratings or grades, but it would probably be four stars or a strong B if it did.
The main criticisms in Philip Kemp's review are that it doesn't quite expunge memories of the BBC version, which had the major advantage of more than double the running time in which to encapsulate a complex and convoluted narrative (he complains that the film's conclusion is a tad rushed as a result of this abbreviation), but he's also firm about the new film's strengths.
I particularly liked his take on Gary Oldman's performance:
Philip Kemp wrote:
Given that Alec Guinness's performance as Smiley is reckoned a peak of his career, much of the interest focuses on Gary Oldman's reinterpretation of the role. He's a harder-edged actor than Guinness, with none of his predecessor's knack for emollient self-effacement. (In the novel, le Carré describes Smiley as "by appearance one of London's meek who do not inherit the earth", which sums up Guinness's portrayal to perfection.) Oldman's Smiley shares the quiet watchfulness, the use of silence to unnerve and elicit the information he's after; but his reading of the character is tougher, more abrasive, now and then allowing his contempt to show through the mask of discreet reticence. Where Guinness's Smiley always seemed internally gnawed by the consciousness of his wife's multiple infidelities, Oldman gives the impression that cuckoldry has simply become part of his prevailing climate - regrettable but not worthy of preoccupation. It's even possible - as it never was with Guinness - to imagine him getting his own back with the occasional fling on the side.
In an interview elsewhere in the magazine, Oldman says that his Eureka moment when wondering how to pull off a convincing alternative to Guinness (a performance he'd admired since its original broadcast) was to base Smiley's voice on that of le Carré himself.