Am i see it right or is the trading fee of bitfunder 5 times as high as the trading fee of btc-tc?
Nah, it's only 2.5 times as high (less if you trade a decent volume). Bitfunder only charges a fee to the seller, BTC.CO charges both sides - so halve the Bitfunder rate when comparing. And use .25% instead of .2% for BTC.CO if you don't use a Yubikey (I'd recommend you use one even without the fee discount - it's more secure and easier than Google 2FA/a PIN).
Ah ok... but still 2.5 times.
Im not sure why a Yubikey should be more secure than 2FA because when it comes to stealing it i think a smartphone can be protected with a password or pin. A Yubikey can be simply used... if it has the website name on it or the thieve knows what its for.
But he anyway would still need the userpass to log in.
Maybe you speak about these new viruses that attack the pc and the smartphone of the user simultaneously. For that attack it would be safer. But i think if someone has the login-details and is a physicl thieve he only has to steal the smartphone or the Yubikey. It wouldnt matter much what it is.
What i like with 2FA too is that you have your smartphone with you most of the time. Yubikeys, maybe for different website different ones... has to be carried with you especially for that reason.
I dont see so big differences in security there.
Yubikey is ONLY vulnerable to physical theft. That's not such a concern to me - computer's hard drive is encrypted so if they steal computer and yubikey they still have no idea what it gives access to (or what my passwords are).
Biggest plus of it is it's so much easier. I use it for every transaction - as I don't have to type in any codes or anything, just touch it and it types the code in. Using Google 2FA is far more tedious and intrusive - which I guess is why most sites haven't even implemented authorising at a transaction level.
I use Yubikey on BTC.CO/LTC-GLobal and Google 2FA everywhere else that I can. Yubikey is miles easier in my view - I'd happily have every transaction on all sites verified by Yubikey. I'd go insane doing that with Google 2FA.
That said, you do raise an issue - that if I want to access BTC.CO/LTC-Global from my smart-phone then I have to disable Yubikey first.
You can use Yubikeys on as many sites as you want - unless they insist that they you purchase from them and run their own Yubikey servers.