Yes they are sweet! -I like the extra room for more gauges!
On another note for you builders notching the frames for any types of additions into it I would offer this engineering tip.
Cut the notch so that the corners of the receiving member are curved instead of square, even if it just a 1/8" to 1/4" radius, thats all you need. This will allow less of a strain at that joint and less likely of cracking or splitting out there. An "arch" is much stronger than an "angle" in any application.
When you buy angle steel or alum, make sure it is 'structural', look at the inside angle and it should be curved, not a sharp 90*
