I was Chief Electoral Officer in British Columbia for the 2005 general election, which was the first fixed-date election at a provincial level in Canada. October 19, 2015, will probably be the first fixed-date general election at the federal level.
One of the advantages of fixed dates, from an election administrator's viewpoint, is that everything becomes like a big project, and you can work backwards. Ideally, you're recruiting your election officers far before the writ is issued. You're not waiting until two weeks before; you're not scrambling at the last minute trying to get training sessions done the night before they go to work. You're trying to do this in a really orderly way. You try to get the best people you can, and you want to make sure that you fit training into their schedules and your schedule. You want to make sure that you have training sessions of like-roled officials at the same time.
So absolutely, having more time to do the training—and the recruitment before the training—really professionally is an advantage, I think, for improving compliance.