I'm doing a side-by-side comparison between SF 10 and SF 13, using a slightly older Windows 7 SP1 platform.
Here are the issues that I have found between 10 and 13. 10 is my standard bearer. I'm forced to stay with 10 because 13 is exhibiting problems like these:

13 doesn't start playing until several seconds after clicking the play button.

13 has a noticeable audio delay when playing back a song in slow-motion. The progress bar will pass by say, a peak denoting a snare drum hit, but you'll hear the actual peak perhaps a few millisec after the peak has been passed. This makes things a bit difficult when building loops.

13 will be nothing but silence when playing back a song. This is hit and miss.

Version 10 does NOT have ANY of the aforementioned issues.

I did apply the latest software update to version 13 after the installation.

I hate to think that I've wasted money on this but this doesn't look good on Magix's part. It's the same old script: A decent software package is sold to a different company, rebranded, given some tweaks, marketed as a later version and it ultimately runs like crap. Nothing I haven't seen before.

Let me know if you have any solutions for this.