Hm... The Strange Parts don't really interest me that much. I mean, I was excited about them until I saw what stats they would track. I'm just fine with my kill counter, really. I might slap a few on my weapons if I'm feeling fancy, but I imagine that I'd just sell them.
Regarding the new crates: They're really running out of options now. I guess I'd just collect the new stranges for the sake of collecting them. Well, I'd use the Huntsman, the Sapper, and possibly the Widowmaker if I could ever get into the hang of it. How would one equip a Strange Sapper anyway? Is there a new Loadout option on the Spy now? (EDIT: Yes there is. Engineer also has a fourth option also for his Construction PDA. I can't even imagine what stats that would track if that ever went Strange..)
Also, I have another spare Strange Knife if anybody is interested.
Oh, and I've been taking a liking to Scout now. Nearly 500 kills on my SF Scattergun already, and the Holy Mackerel is funny as hell :3