I have a Uniden BC 246 and it works very well when I'm near the transmitters (ie. at the airport), however as mentionned in one of the other reply, it is advisable to get another antenna for increased performance. I live only 15 or 20 miles from halifax international, and although at the airport itself from one of my favourite viewing spots the reception is crystal clear, from my house, it is sometimes difficult to hear the airport (althogh aircraft are no problem, for obvious reasons, because they are above the horizon...)
On another note, I was very much looking forward to my first flight with my scanner (since as mentionned in my other post today, not every airline has channel 9 to listen to ATC). However, was surprised to find that once airborne, it becomes almost impossible to hear ATC within the fuselage of the plane... it's a little better to hear the cockpit since the transmitter is close by... so it became hard to keep up with freq changes when moving from one sector to another since you usually miss the centre's call to switch to the following freq... however the 246 helps in that it has a close call feature which homes in on any close radio transmission without knowing the freq and locks on that freq, so if you select that you can still follow the cockpits transmissions without having to follow the freq reassignments... but it was still a letdown, because the idea I think is to be able to hear all the OTHER aircraft around you... (at least for me as an air controller, this is the most interesting part)