Sondheim and Weidman's Road Show has been knocking about in various incarnations and under several different titles (Bounce, Wise Guys, Gold) since 1999. Phil Willmott's scintillating revival at the Union makes a strong case for the musical - a fast moving, slightly exhausting account of the real life story of the Meisner brothers who went off to seek their fortune in the early 20th century Alaskan gold rush and ended up profiteering mightily in the 1920s Florida real estate boom - without ever quite convincing that this is top drawer work.

The score has some real gems but the uncharacteristic (for Sondheim) folksiness of some of the music sometimes sits uneasily alongside the complex syncopations and melodic unpredictability that are the frequent trademark of this most elegant and urbane of songsmiths. The lyrics are, as one might expect, spot on: witty, concise, then occasionally and unexpectedly poignant. The main problem with the piece is that this is not a story that cries out for musical treatment, despite the sterling efforts of these two master craftsmen (Weidman's book capably and dynamically tells the story of the mismatched brothers in flashback, taking in a bewildering array of locales and relationships, but never alighting on anything long enough to provide true dramatic meat).

Despite this, Willmott's staging contains much to enjoy. This version scores over the 2011 Menier Chocolate Factory premiere by casting actors who fully convince as brothers (David Bedella and Michael Jibson were individually brilliant in that production but were never quite believable as siblings). Here Andre Refig unleashes buckets of charm and a terrific singing voice as the ambitious, amoral Wilson Meisner - never far from the nearest gaming table - while in the meatier role of quieter, genuinely talented Addison, Howard Jenkins gives a superb performance, skilfully suggesting the innate goodness of the man but with an undertow of worrying melancholy. He also sings like a dream.

As their controlling mother, Cathryn Sherman is a commanding presence and exquisitely delivers what is probably the finest number ("Isn't He Something" in which Mama Meisner fetes the ever absent and unreliable Wilson oblivious to the resentment she is stirring up in her other son). Sherman's performance of the song is so riveting it is a pity that it is accompanied by a superfluous and distracting bit of choreography for Wilson: a rare staging misstep (elsewhere Thomas Michael Voss's work is impressive). Joshua LeClair is amusingly temperamental but ultimately touching as the sensitive rich kid Addison fleetingly finds happiness with. The hard working ensemble all register strongly, collectively and individually in a wide variety of roles and the choral singing is excellent throughout, as is the playing of the three-strong band under the direction of Richard Baker.

Jess Phillips' attractive frame-dominated set is evocative, adaptable, and inventively lit by Jack Weir. Willmott plays up the gay aspect of the story in a way that never feels forced but interestingly illuminates Addison's slightly isolated, remote character, brilliantly realised in Jenkins's haunting performance.

Road show may not be vintage Sondheim but it is a meticulously crafted, highly entertaining piece, and Willmott's superbly paced, elegantly staged production is a must for fans of serious musical theatre.

Running time: 1 hour, 50 minutes (no interval)

Road Show runs at the Union Theatre until 5 March.