I think Jim is right on the money myself. I've seen many debates (and participated in my share) on the sound quality of "x" vs "y" hardware and/or software.

Personally, I think the final impact of your recorded song is based roughly on this order of importance:

1. 60% - Quality of the musicianship (songwriting, vocal chops, etc)
2. 25% - Quality of the arrangement (instrumentation, parts working together, etc)
3. 10% - Quality of the engineering (recorded and mixed well?)
4. 5% - Quality of the equipment (software/hardware)

Feel free to debate the sequence and percentage of some of those items, but I think that if Chuck Ainley was using Protools or Logic instead of Nuendo, the artists on the CDs he's mixed would still have their Grammys.

Basically, if you don't have #1 and 2 above, then you're fighting an uphill battle. #3 and 4 will only make a bad song sound good. Some people put #1 at a much higher percentage...

Side Note: If you're experiencing speed changes in the digital realm, then you probably have a mis-match in sampling frequencies. The most common mis-match is recording something at 48K but playing it back at 44.1K (or vice versa if it's faster).

Larry
http://www.audibleresponse.com
http://www.myspace.com/larrywilliamsproductions
...now writing/producing with Natascha: http://www.myspace.com/nataschacorrigan