I also don't hear anyone else with my audigy 2 card. I also don't think the stock sounds of IL2 are bad or sound 'like a lawnmower' as I have read others say. As Oleg said, it was designed to be played on a high end sound card, which it sounds good on. I can hear the whine of the turbo in a 109, and all sorts of little pings and knocks in the aircraft engines. Even the P51 has its distinct whistling sound with my Audigy 2.

But I am glad that BoB has this fixed and will run on a wider range of sound cards and onboard sound.

Same card, and I don't either, but i'm using ultimatesoundV2 wich is specially designed for to correct the SONAR problem. When using stock or UP i hear others when they get close, it's not as bad as i have experienced earlier with my hercules persono III or onboard AC97 and not as efficeint as a SONAR help, but it still destroys immersion.

Still, it seems we have voters who enjoy the SONAR help, i wonder if they use other helps too or fly full switch ? Maybe it could be a difficulty setting in BoB ?

The real problem isn't the sound quality I guess. It's just that you won't meet a lot of people that will actually use a good soundcard or mod to get rid of hearing people close in - you'll rather find the opposite. The problem is that some people WANT to hear others approaching to gain an unfair advantage. But if they say it's fixed... well, I never saw a game where cheating was impossible but let's hope for the best :P