rmcellig wrote:If for example the sound is recorded properly in the right channel but rather weak in the left channel, all I do is highlight the sound in the right channel and paste it in the left channel.
I don't understand why you want to do that. What you achieve is two-channel mono, ie, waste of disk space and processor cycles. Either, (a) stereo matters, in which case you should normalize each channel individually (you can do that in SS, but I don't think you can do it in Audacity); or, (b) stereo doesn't matter, in which case you should mix down to mono (Audio > Resample), which takes half the space and half the time to process.
rmcellig wrote:The other thing is that in Sound Studio when I want to save an aiff file as for example an mp3 file, I go to file save as and then select MP3 option and save. The save is pretty quick for a 2 hour aiff file.
It may say "save", but you don't actually save an AIFF file as MP3. What you do is encode a
lossless audio format into a different,
lossy audio format. In version 2, SS uses QuickTime to encode in MP3, ie, the same encoder iTunes uses. It is indeed fast, but I believe connoisseurs argue the quality leaves much to be desired. Audacity uses LAME
http://en.wikipedia.org/wiki/LAME, which can be much slower. On my machine, LAME 3.97 is roughly an order of magnitude slower than QuickTime.