The translation is good (the same as any of their other series if you are familiar with them). Better QC than AEN, no surprise there, and the sentences flow well.

Just don't expect to see another episode subbed by them. gg is fairly vocal about this being subbed only because there was no Code Geass this week (and it even says that right after the OP).

My only problem with their translation is their choice of terms. I prefer AEN's "technician" over Rumble's "Meistar" and gg's "Master", and gg opts to translate "Kishin" into "Demon God" which while correct, doesn't seem to fit the context of the series all that well. In Soul Eater, "Kishin" seems more like a proper noun than some other term, a title rather than a description.

It's mostly personal taste, but their quality is good. I got a little lag during the OP (just like I do with the Code Geass releases) and that seems to just be a standard of gg's not-quite-optimized encoding on HD releases, or it's whatever they do to their karaoke. AEN and Rumble (and Eclipse for CG) have never given me the problems gg releases do during OP sequences.

I say go for it while you wait for Rumble or whoever.