Many cable modem users accustomed to zipping along the Internet at blazing speeds say that recent changes to Comcast Corp.'s fast Internet service have them puttering in broadband's breakdown lane.
Since last month, Comcast has been transferring customers of its cable modem Internet service from the network of a contractor, bankrupt Excite@Home, to Comcast's own routers, servers and fiber-optic lines - a network it built from scratch over the past year.
But some users say that after being switched, they have been troubled by drastically slower download speeds, an inability to access Web sites, fewer features and difficulty reaching customer service representatives.
The switchover made headlines in Michigan and northern New Jersey last week as some users in those areas complained of lengthy outages and frustratingly slow downloads.
"Prior to the transition, it was blazingly fast," said Brian Volz, a Comcast Internet subscriber in Hainesport, N.J. "It just crawls."
The service costs $40 to $45 monthly; Comcast increased the price in October. "I'm paying more and getting less," Volz said.
A Comcast official said the transition was going relatively smoothly.
"The vast majority of the cut over is going very well," said Dave Watson, executive vice president of sales, marketing and customer service for Comcast's cable unit.
Watson said that there have been "isolated pockets" of problems but that the company expected some bumps with such a complex undertaking.
Comcast is fine-tuning technical aspects of its network, and any inconvenience to most customers should not last more than a few days, he said.
It's hard to quantify how many customers have been affected. Comcast said it has switched over about 300,000, or nearly a third, of its fast Internet customers nationwide, most without incident.
Nonetheless, a visit to the Internet site www.dslreports.com yielded plenty of postings by disgruntled .
Comcast originally planned to move its high-speed Internet customers from customersExcite's network to its own by the middle of this year.
But after a bankruptcy judge ruled in November that Excite could shut down immediately, Comcast and other cable firms bought themselves time by agreeing to pay Excite a total of $355 million to remain open until the end of next month.
In the aftermath of Excite's collapse, Comcast now maintains its own Internet servers, routers and other specialized network equipment, along with its cable television equipment.