I moved to Portland from California in 2001. I love it here, and can't imagine ever moving back. That being said, the big adjustment for me (and for many folks moving from further south) isn't the rain. It's that the days are so much shorter in the wintertime, and even when the sun is technically up, you can't see it through the cloud cover.
It's easy to love Portland in the summer (and, having grown up in Sacramento with weeks of temperatures over 110 degrees, I was very surprised to discover that I actually like summer now). The real test is whether you still love it in the middle of your second or third winter. ;>
Another Sactown => PDX refugee here. Pretty much love the weather year round. But I loved Sacramento's rainy winters, so I'm likely wired that way. It's taken a while to adjust to the idea that summer is a season where you actually go outside instead of hiding indoors with a/c.
I resonate with the "filthy and dilapidated" comment though. I blew off Portland as a dirty industrial town for a lot of years before moving here. It still has a lot of that heritage, and if you're from a place that constantly tears things down and rebuilds, you likely won't understand it here.
It's easy to love Portland in the summer (and, having grown up in Sacramento with weeks of temperatures over 110 degrees, I was very surprised to discover that I actually like summer now). The real test is whether you still love it in the middle of your second or third winter. ;>