Pete,
I've been to Bandon in March, April and May for four days/three to four nights each time, and I think I've had one sunny day combined. The weather has ranged from heavy sleet necessitating taking refuge in a deep bunker to playable with proper protection. I can think of only a handful of days in Ireland where I was more uncomfortable playing golf.
Those on the West Coast can watch the weather maps and catch a break during the low-season. For me and many in my part of the country, the UK is the superior option. All three times I've been to Bandon I came away appreciating the experience, but always thinking that I don't need to go back. It's been a while since the King Putter. I could be talked into returning in the not-too-distant future.