It's a very hot trend lately -- condo living. But a News 3 I-Team investigation finds more than ever, you need to think before you buy.

Linda Eggert reports that condos are changing the local landscape, and why some experts have some concerns about a supply soaring beyond demand.

One longtime realtor told News 3 condos have helped give him his best sales year ever.

Lured by urban amenities, the Madison skyline is changing, and putting a lot of construction crews to work. It seems there's a new condo on every corner. Buildings in every shape and style just keep going up, aiming for some new markets like baby boomers in transition.

After raising three kids on the Westside, empty nesters Frank and Olga Scarano want comfort and convenience.

The Scaranos will see both lakes from their 12th floor unit in the new Marina Condominiums.

The $17 million high rise overlooks Lake Monona, and has 55 upscale condos ranging from $380,000 to $1.7 million.

The Scaranos will pay between $500,000 and $600,000, and they feel good about going big -- tapping profits from their first condo.

But a News 3 investigation finds not everyone is crazy about condos.

“There's been a rampant overbuilding in the condo market for probably the last 3 to 4 years," said Jay Reifert, an exclusive buyer agent.

Reifert thinks condos are such risky investments that for a year now, he's refused to help his clients buy any.

He even wrote a letter to the newspaper. Reifert believes there aren't enough people to feed a market he says is way overbuilt -- and still building.

Just last week ground was broken on a $110 million condo development.

“That's not going to stop until someone gets hurt. And when I say someone I mean until the marketplace shows that it's overbuilt, and then it's too late," said Reifert.

The local realtor industry, however, disagrees.

“We're not seeing any signs that would suggest that it is overburdened or overbuilt. It's definitely a marketplace that has increased,” said Kevin King, vice president of Realtors of South Central Wisconsin.

That’s in part because of single and young couples. But News 3 finds even some real estate experts have a condo concern.

“That's the part of the market that'll evaporate first at the first sign of bad news," said Tim Riddiough, director of the UW Madison Real Estate Center.

Riddiough says supply and speculative buying might make some condo purchases risky.

“You can go either way but I think it's particularly dicey now, in the condo market. If you're looking at it as an investment I don’t know that I'd recommend that," said Riddiough.

In January, News 3 finds Madison had more than 10,000 condos. That’s about 2,600 more than just 2 years ago -- a nearly 36 per cent increase.

So far this year, permits for another 370 units have been approved, and lots more are in the pipeline all over the city. Even some industry insiders are a bit nervous.

“I would hate to see our inventory get totally out of whack," said Sheridan Glen, a First Weber Marina Condo agent.

Glen worries most about a glut of mid-priced condos.

“If we have thousands of mid price units come along, in other words, pinch the price range between 150 and 300, and there's hundreds of those types of units out there, it's going to put a pall on the entire marketplace," said Glen.

Glen wants developers to build both quality, and diversity in price. He says that way the condo market can build to new heights, without risk to investors.

Fueling the fear over too many condos is the fact that more big apartment buildings, some with high vacancies, are converting into condos. Some say that's also helping glut the market, though the local realtors group insists there's plenty of demand to go around. Still, even it admits condos are trending toward a buyer's market, with nearly 1,600 units on the market, taking an average 8 months to sell.