* Sochi became "world's largest construction site"
* Putin under fire over high cost of Winter Olympics
* Local residents enjoy festive atmosphere at Games
By Timothy Heritage
SOCHI, Russia, Feb 10 (Reuters) - After putting up for years with dust, noise and traffic jams while their drab Russian resort was transformed into a modern sports hub, the people of Sochi can finally judge for themselves whether it was worth it.
As the $51-billion Winter Olympics got into full swing on Sunday, the answer from spectators, seeing the Olympic Park up and running for the first time, was a resounding "Yes".
"It's just fantastic," Sergei Klyuyev, from the Adler area where the park was built, said as he walked through with his family, admiring the state-of-the-art stadiums and enjoying the party atmosphere.
"There's been building work here for five years but look at all this around us. We regret nothing, not even the cost."
Some Sochi residents are still angry that hosting the Games meant turning the city into what even President Vladimir Putin described as the world's biggest construction site, and have set up a website - Blogsochi.ru - to vent their spleen.
In the heart of the sub-tropical city on the western edge of the Caucasus mountains, cranes still tower over half-finished apartment blocs.
But the critics were nowhere to be seen at the venues far from central Sochi as the Games began, partly because some have been barred from travelling to Sochi and partly because of the good impression created by the new stadiums.
Putin hopes the Games will portray Russia as a successful and thriving modern state, and protests would threaten that.
"There are definitely people who had a hard time of it here," said Yevgenia Mertilova, referring to the hundreds of people whose homes were razed to make way for Olympic buildings and were mostly housed elsewhere by the state.
But, as she walked beside the main Fisht stadium with her nine-month-old baby, she said: "Look how good these stadiums are. After the Games there'll be a trade centre here, which can only be a good thing. I'm impressed."
"BETTER THAN 1980"
On one side of the park, men in red peasant tunics and women in colourful blue and white dresses performed traditional dances to the music of balalaikas.
In the centre, the Olympic flame burned fiercely in its cauldron towering over the park. In fountains beneath it, shoots of water rose and fell to the music of Pyotr Tchaikovsky.
"I was at the Moscow Olympics in 1980 and this is much more grandiose," said Nadezhda Kharitonova, a woman in her seventies who was dressed in her red Sunday best as she walked hand in white-gloved hand with her husband.
"It's all down to Putin. Without him, it would never have happened. Whatever the cost, it was worth it," she said.
That will be music to Putin's ears after months of carping at home and raised eyebrows abroad over the high cost, plus criticism of his stance on gay rights.
Russia's first medal of the Games brought whoops and cheers from a crowd watching on a big screen, and concerns about security seemed to have been forgotten as security officers patrolled the perimeter fence on horseback.
There were, however, a few in the crowd who were still unhappy at the hefty price tag.
A man who gave his name only as Vasily said he had taken leave from his job as a clothes designer to work as a cleaner at the Games so that he could soak up the atmosphere.
"It's a once-in-a-lifetime event. I wanted to see it from the inside," he said, a broom in his hand. "It's all amazing but of course the cost is too high for Russia. You should really think more about the many poor people."
Putin says the Olympic construction will give the city and region an economic boost. Critics doubt this and Blogsochi.ru posted its latest criticisms as the Games got going.
"Because of the Olympics endless queues have appeared in Sochi like queues for sausage in Soviet times," wrote Alexander Valov, who has repeatedly used the website to draw attention to problems in Sochi.
But even he wrote of an "unforgettable experience" at the Olympic Park and the criticisms on the site were interspersed with entries celebrating Russia's first medals at the Games and unusually positive interjections such as: "Hurrah! Well done!"