Fedex truck bringing me an early present on Friday: my first prime L lens, Canon 300mm F4 non-IS in excellent condition.

Ian, weren't you using the IS version that you borrowed from your friend? I might let you borrow this one after I have a chance to play with it a little bit, just so you can compare the two.
Awesome! I don't think you'll be disappointed

It's probably a lot lighter than the IS one.
I actually just got my first L series lens of my own! Woot! Desiree bought me the 70-200 F4, non-IS. It's tiny - barely bigger than the cheapie 70-300 $150 zoom I've basically given up on because the colors get all fucked up.
And it's about half the size and a third the weight of the 300 - which I've mostly been using for candids at events, and for that, it's kinda sucky - EVERYONE knows you're taking their picture with it, and you have to be in a large rooom to get far enough away anyway.
The range of the smaller lens is perfect, and the colors are the lovely smooth rendition that only L series (and the 85 F1.8) seem capable of reproducing, at least on a Canon.
Bokeh isn't that great, which suprised me, as the aperture blades create a near perfect circle - just seems a little harsh next to the 85 F1.8, even at similar aperture/focal length settings. Not bad, just not
great. But great value for money

Very happy with it
And yes, still got the 300mm F4 to test against yours Alex! Just lemme know when you want to do a back-to-back test
Flash has arrived in Virginia today... hopefully back by Christmas...