On a good day, it used to take Caryn Gardener at least an hour to get to her receptionist's job in downtown Washington from her home in Springfield. Now it takes her 15 minutes.

Gardener is one of hundreds of apartment-hunters who have knocked at Crystal City's doors looking for a place to live since Metro came to the glass-and-concrete complex in South Arlington. She considers herself lucky to have found one:

"When I heard about an effiency open at Crystal Plaza I couldn't believe it; I couldn't get down there fast enough. Now I can walk from my apartment to the Metro station without ever having to go outside. I think it's super."

When Metro came to Crystal City in July, it brought the cluster of high rises a new-found popularity as a place to live, a place to work and a place to cdo business.

Sylvia Seymour, assistant resident manager at Crystal Plaza apartments, said apartment hunters "have been falling all over themselves trying to get an apartment here since Metro opened. The phone never stops ringing. We've never been short to tenants, but if we could fill all the requests we get now, we'd running 200 per cent occupancy."

Other Crystal City resident managers confirmed that there been a "run" on Crystal City apartments, which includes Crystal Square and Crystal Plaza on the east side of the highway - linked to Metro and shopping arcades by underground tunnels - and the four Crystal Houses and Crystal Towers apartment buildings on the west side.

Metro also had brought badly needed business to Crystal City's new underground shopping center that was built with the subway in mind, although some storekeepers in the submerged shopping arcade complain the expected Metro to bring even more shoppers.

Some shopkeepers say that Mertro's schedule - no service on weekends or after 8 p.m. - eliminates would-be weekend and evening shoppers at Crystal Underground. And Crystal City residents complain that they are stranded at the times they would like to use the subway the most.

Motorists driving past Crystal City - on the east side of Rte. 1 from 15th to 23rd Streets - sometimes liken it to giant tomb, cold and lifeless. At times, Crystal City, whose 21 buildings are the work place for 20,000 and home for 5,000to 6,000 residents, does seem quiet as a tomb. But a lunchtime, Crystal City's underground arcades start hopping, and the apparent inactivity above ground becomes deceptive.

Secretaries from downtown Washington, tourist from National Airport and hotels in the Crystal City area, business, government workers and many people in Navy uniforms pour into the underground. Most are from the towering office buildings in Crystal City, but many have come from the Metro station. Like a downtown business district, children are conspicuously missing.

Some take to the submerged ice skating rink for a turn or two; others tote bag lunches to cement benches in a cement plaza surrounding the rink. During the noon there is a continual line in front of the Crstal Plaza Hot Shoppe. The Metro trains pulling into Crystal City are crowded with shoppers and people seeking new places for lunch comming from the District.

As abruptly as the underground fills with people in late morning, it becomes nearly deserted in the middle afternoon leaving storekeepers staring over their cash registers at the few passers-by in the arcades.

For some persons the enthusiam for Metro is based on future. "Metro is going to make this place," said Andy Zimmerman, whose family owns Larimer's gourmet in the Crystal Underground shopping center, which is decorated with a Gay Nineties flair, a curious contrast to the stark contemporary look of Crystal City's exterior and the tiled tunnels leading to the Metro station. "My business has gone up 25 per cent and there's no doubt it's going to get better."

But about six blocks away, through the underground tunnels that links Cryatal Underground to the Crystal Plaza shopping center, business is almost extremely from Crystal City office workers.

"We're far from the Metro station for the subway to do us any good," said W. J. Mazie of Crystal Plaza Jewelers. "But the business here are already heavily trafficked byt the people who work here."

Almost everyone interviewed at the Crystal City Metro station, including those who live there and those who commute there daily, have one complaint or another about Metro, although all admit the subway is a boon for the area.

The main complaint about the rapid transit system it its hour. Also, some merchants note that while Metro has brought more customers, it also has brought more shoplifters. Government workers and business say they have to allow longer than they would like to make appointments at the Pantagon or downtown for fear of unexpected Metro delays, although they add that such delays are less frequent now than when the subway opened.

Residents and workers at National Center and Jefferson Plaza, other high rise development which flank Crystal City to the north and south and are regarded as part of Crystal City, say they are too far away from the Metro station to be without bus service, which bus service which was phased out when the subway opened.

Downtown secretaries say their lunch hours do not permit them to spend 30 or 40 minutes round the trip on the subway only to speed 20 or 30 minutes to eat or shop.

"I don't care what anyone says, Metro is the greatest," said Michael Trefa, an assistant resident manager at Buchanan House, a high rise apartment building to the south of Crystal City." All I had to so was ride the bus back home to the District a couple of times to know what a difference the subway makes. If Metro weren't around, I wouldn't working here."

"The only thing I have to go out for is fresh air once in a while ," said Madeline Stackman, a public relations counselor who moved to Crystal Plaza last week. "And it only takes me between eight and 10 minutes to get to my office near Farragut Square."

Crystal City used to be as far as an hour away from downtown Washington by bus.

Pauline Katz, a Crystal Plaza Plaza resident 11 years and a cosmetics saleswoman at Jelleff's department store in the Crystal Underground shopping center, says she and her husband rent a car when they want "to get out of cemment city for a while.

"Otherwise, everything we need is right here, wehter it's conveniece or privacy," said Katz, who is among the 15 per cent of Crystal City residents who also work in the complex.

In addition to the immediate changes Metro has brought this protion of the Rt. 1 corridor - a spawl of warehouses and industries 15 years ago - Metro is the catalyst for more changes and more growth in the Crystal City area.

"Metro has enabled us to increase the size and scope of Crystal City," said Robert H. Smith, president of the Charles E. Smith Building Corporation, the company that conceived, built and now manages Crystal City. "It has let us broden our vision of what Crstal City can be."