Bitcoin-Central is great for EUR (with SEPA transfer for cheap). They were down the first week of April but there were online nons-top since 2011 before that and on 10th April it was the only exchange website I know that was working all time long during the crash down.
However it's maybe not the best for quick buy and sell to take advantage of small fluctuation as there is a little less volume. Expect to get some inertia during fast variations (but could be a good point too if you're clever and a little lucky).