How long until you plan to upgrade the remaining switches? A week or so?
In general I would approve of this unless you plan to immediately begin using a "new feature" specific to 5.0.1.
Looking through the release notes, I don't think that's a concern here.
I've attached the release notes so you can check to see if anything pertains to your specific configuration.
I don't think there will be a problem specific to the servers or arrays though.