Sorry, I can’t comment on what is going on with BitGrail. I bought my XRBs there earlier before they got into their recent problems. Haven’t been following the current situation closely. Whenever you do transfer out, I suggest sending a small amount as a test and when it registers in your wallet, send the rest.
As for the sync taking so long, I don’t have any real idea what drives the periodic pauses in updating the first number. If you are still a long way from fully synced (currently 5,405,188 blocks as the first number), then I really suggest that you follow the procedure that I mentioned in my first reply. It is the developer-approved procedure for a mass transaction download.
Personally, I really don’t like the idea of web wallets for security reasons. Your private key (the seed) is intended to be private. Sharing it with a web site gives them the power to steal your money from you. However, they have been honest to date and others have used them successfully. Just understand that you are trusting someone you haven’t paid to keep your money safe.
Also, for what it is worth, I did confirm that the next wallet should address this startup problem. They got caught with the massive growth of RaiBlocks about a month ago and it uncovered some scaling problems in the wallet. Their new wallet is going into beta testing soon, but it will be a while before it is fully tested and available for general use.