I'm sure that if I called them they would say it's my internet connection, and they would probably be right. My DSL is pretty crappy. but I had a different company beforehand, and I never had a problem. It could be that with a decent connection there wont be a delay, but even when there's no delay, the quality isn't so great.
In short, if you're a kollel guy on a tight budget, this costs what 6 months costs with a paid per month company, and it's manageable. But I wouldn't recommend it as a primary line. I signed up with 018 and pay only 8.5 ag. per minute to US, and have that as a backup for when it's really crappy.
Then again, someone with a faster/more stable connection, may have a completely different experience.