There are only 2 datacenters servicing all regions: 1 in Japan for JP players and 1 in Canada for NA and EU players. So everyone in Europe is stuck connecting to Canada and I haven't heard anyone complaining about unplayable or even BAD pings. My advice would be to try an NA/EU server and see how the lag is. If it's okay, roll on any of the big NA/EU servers. If it's bad, roll on a JP server. It's not like you're stuck with whatever server you initially try out. The worst that'll happen is you waste an hour and have to reroll on a different server.