Its location on the north shore railway line - and its proximity to major centres such as St Ives, Hornsby and Macquarie Park - has long made it a top pick for house-hunters who value convenience.

But changes to zoning in recent decades have created distinct housing tiers within Pymble which have wreaked havoc with buyers' expectations.

"It's a real mixed bag," says Chana Scotcher, whose eponymous real-estate agency represents prestige property across the upper north shore.

"Anything close to the Pacific Highway has been zoned as medium/high density, which has created a lot of apartments.

"Whilst that was happening, the council was also protecting some of the areas that are farther away from the station, so even if you have a huge block of land in Pymble you can't subdivide it."

Scotcher holds the listing for 53 Telegraph Road, a six-bedroom Federation home with a swimming pool, tennis court, large grounds and separate guest quarters. The guide price is $8.5 million.

It's one of dozens of homes in Pymble of similar proportions and quality.

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Scotcher says Pymble has become popular with professional Australians who have spent time abroad. "They become well-heeled overseas and when they finish their stint they're seeking a big estate back at home," she says.

The comparative value of the prestige property in Pymble has also made it a popular choice for couples who have built equity from scratch.

"A local couple may already own a couple of properties in the area and want to upgrade," Scotcher says. "They've got equity in two properties, perhaps, so they'll sell those two properties and upsize to something more substantial. Then they will try to live there for 20 years, until their children leave home and it's time to downsize again."

A medium tier of humble family homes creates even more diversity in Pymble and appeals especially to young families drawn to the area by its well-regarded schools.

"Pymble is more family focused, very much so," says Jill Smith from Savills Cordeau Marshall Gordon. "Pymble Public is a very popular primary school and a lot of people want to be within its catchment area."

There's also Pymble Ladies College and more than a dozen other schools within a 30-minute drive of Pymble Station.

The suburb's proximity to so many schools made it the obvious choice for Sue Turner when she decided to find a bricks-and-mortar location for her business The Uniform Exchange.

Now, families from right across the north shore visit her Pacific Highway shop to buy second-hand school uniforms or sell items that no longer fit.

Turner moved from St Ives to a cottage in Pymble when she opened the shop two years ago. She says she loves the suburb's leafy ambience.

"From my cottage, all I can hear is church bells on a Sunday and the occasional ambulance," she says. "The trees absorb all the sound."

Pymble does have its quirks, she says. "The highway cuts it in half. You wouldn't believe how difficult it can be to get from one side to the other. But once you know where it's going, it's fine."

The diversity of housing stock in Pymble makes meaningful data analysis difficult. But agents agree that houses in the suburb have soared in value recently. According to Domain data, the median house price has risen 123% per cent.

Apartments have not fared as well, perhaps because of the flood of new apartment buildings along the highway. The apartment median has risen just 34 per cent over five years.

Scotcher believes prices in Pymble may now have plateaued.

"Until recently we had a vast number of potential buyers from China, however that has slowed now because it's become more difficult for them to get their money out of China," she says.

"We're getting more inquiries now from locals."

Smith says the suburb's assets won't stay secret for much longer. "Right now there is still good value to be had - but already you've got to look a bit harder than in some other areas," she says.