I don't own a Blur but I very much like Kershaw's knife offerings. All I've had experience with have been excellent. However, over the years I've learned to really dislike assisted opening knives and Kershaw has too many of them that cannot be deassisted and maintain function. The Blur is an exception since it is reported to be able to be deassisted and that is a definite plus, IMO. But whether the AO is a pro or con is personal. The Blur is more generally available at a lower price than the PM2 and those are definitely features in its favor.
Like the Kershaw's, all the Spydercos I've owned have been excellent. I do own a PM2. It has become one of my favorite knives. I put it on a par with the approximately same sized Spyderco Gayle Bradley folder and ZT 0550 as far as build quality and functionality. It's a joy to use and, like all Spyderco knives I've handled, it feels like it was designed for my hand. Negatives include cost and availability. Possible negatives are the Spyderco blade hole that some people dislike and the blade shape that tapers to a very narrow, thin point that can be fragile if abused.
I'm sure either knife will serve you well.