Hey guys, I was waiting for this game for so long, but then noticed it on Steam one day and immediately bought it, and now I see it is on GoG too.

Is there any difference? I noticed playing the Steam one that there is some stuttering issues. Is the GoG one better?

They same, +DRM-free (so GOG is always work better, maybe a little bit).
Gmae not so perfectly programmed (rare case when game really is partially a reason for compatibility issues). But both GOG\Steam should be ok.
Some ingame bugs can happen.

Most likely if you install GOG version you faced same issues.

[url=http://www.pcgamingwiki.com/wiki/Diggles:_The_Myth_of_Fenris]http://www.pcgamingwiki.com/wiki/Diggles:_The_Myth_of_Fenris[/url]

Make sure game work not faster than 60 fps. Or probably even 30.