With a fifth edition in the books, The Straits Times Run in the City is still considered by most industry observers and running enthusiasts as the new kid on the block.

Yet many also say it is run like a well-oiled machine, quickly growing into one of the main players in a calendar where mass running events are ubiquitous.

Those who have taken part in several editions of the ST Run over the years, in particular, say they have witnessed first-hand how the run has matured.

Mr Oh Wai Some, 55, took part in his third instalment of the annual run yesterday. He said his experience has improved each year.

"I would definitely rate this year's as the best. I can feel a difference - it's getting more well-organised," said the manufacturing firm manager, who completed the 5km race.

"Previously, there would be a point along the route where non-runners were allowed to cross the path, but things are now segmented nicely."

He lauded the more party-like atmosphere at this year's post-race carnival, held at the spacious Padang venue.

Musical acts like local band Jack & Rai entertained runners with live performances, while several food vendors set up shop to fuel the weekend warriors' post-run appetites.

But while food and beverage booths, as well as freebies are a common sight at mass running events, what has kept many participants coming back year after year is an element of "surprise".

Many say that the ST Run, with its penchant for introducing alterations in its route or venue, can be counted on for a refreshing change.

The inaugural ST Run in 2013 took place at Punggol Waterway, before moving to the Singapore Sports Hub for the next two years. It ended at the F1 Pit Building last year.

Said Mr Bu Chee Chuan, a 38-year-old security officer who has taken part in four of the past five editions: "It's a nice change and lets runners get a taste of something different every year."

Miss Heidi Chan, a civil servant who was participating in her second ST Run, added: "I like that the route changes - it keeps things interesting and you know that something will be different when you come back."

But even then, the 24-year-old said there was special reason in picking the ST Run over the countless other runs held each year; $1 of the fee from every registration is set aside for The Straits Times School Pocket Money Fund.

"There's added meaning in taking part in this event," said Miss Chan, who completed the 10km race yesterday.

Those who are planning to attempt longer distances in the near future appreciated the partnership this year with the Standard Chartered Singapore Marathon (SCSM). The SCSM will be held in December, allowing the ST Run to act as a lead-up run.

An eight-month training programme was launched to help runners prepare for both events. It is helmed by national marathoner and 2013 SEA Games gold medallist Mok Ying Ren and is featured every Saturday in The Straits Times.

Said Ms Doshila Neergheen, a 36-year-old teacher who ran the 18.45km race with her husband yesterday: "It's a great strategy to bundle the big races. We were planning to run the 21km (half-marathon) at the SCSM this year, so it's a natural choice that we signed up for the ST Run.

"It's the perfect deal for us, because the lead-up is well spaced out."

But even with a smooth run that had few hiccups, there remain aspects of the event that runners hope will be improved in the future.

For one thing, some say signage directing runners to the start point from major transport stops like MRT stations could be more visible.

All things considered, however, from the youngest participant at four years old to the oldest at 91, and from first-time attendees to returning runners, most left the Padang yesterday with a firm belief that they are likely to come back for another edition.

Said 54-year-old administrator Santie Gunasekara: "You don't have to worry about going too slow, no one is going to laugh at you, and there is such a family atmosphere. It's a run for everyone."

• Additional reporting by Alvin Chia