I used it for voting and it is working. The UI is really nice and easy to use. I was a bit worried about trusting at the beginng, since there is not an official statement saying this wallet is 100% safe. However, I just took the risk considering it have been recomended by several BP that claim they know the team behind greymass.
Only thing I can say is that it worked for me and the vote was casted immediately and I even check the tx at eospark.com