I have both the Yasaka Sweden Classic and the Donic Appelgren Allplay with Yinhe/Galaxy Mercury 2 on both sides. I'm a beginner but if you're debating between these two, these are the differences I've noticed:
The Appelgren vibrates with a harder, more distinct click. The Sweden Classic has a more muted thud.
As far as playing characteristics go, very similar but at slow hits or passive blocks, the Appelgren hits just a bit harder. At harder shots I didn't notice a difference but my technique isn't yet consistent anyways.
The handles, both flared, are quite different. The Appelgren has a beefy handle that is easy to grip with your full hand.
The Sweden has a much thinner middle part, so you mostly touch it at the blade side and at the end of the handle, but not so much in the middle. Personally it feels easier to flick at the expense of a secure feeling.
For what its worth, a friend who plays a good spin and control type game prefers the Sweden, and really loves this setup with the Mercury 2, as do I. But most people prefer the Appelgren for the handle. Hope this helps.