Okay, I couldn't wait for the pad to give it a whirl, so I popped the B pad back in place, kept the B key closed, and played long tones up and down the horn. It's fantastic! I'm stunned that such a phenomenal instrument can be had for less than $400. The tone is so nice, and it's so easy to play. I was able sound everything from Bb to E on the first go, and the upper octave soared right out. I usually have to work upper D# and E a bit, but not on this horn. They were right there, fat and happy. I also tried overtones on low Bb and got them all out on the first try, and they also rang out pure and beautiful. I still need to get the pad fixed, but I have a feeling that this back-up horn is likely my new everyday horn and my YAS-200 is headed for the back up role.
Sorry for the naive enthusiasm here, but it didn't occur to me that this would be such an upgrade. Very, very cool!
Thanks so much for everyone who chimed on this thread, even those who counseled me to pass. All of your advice was super helpful! I really appreciate it!