Dave, when you did the test with UART serial, you were using a inverted bit setting.
Yep. TTL serial is conventionally active low!
Trap for young players there... Zoom in at various points (eg. 32:30) and you can see it treating the first low after a high as the start bit and then sampling after that. It then marks the spot after the last bit in red because the stop bit is missing!
Personally I think the lack of advanced triggering isn't that big of a deal because of the massive sample memory and excellent export capabilities.
I'd agree with that, but you really need a search function to seal the deal. "Record for ages" + "Search for interesting bits" and you can drop the old "I better set up my trigger right and wait..." mindset for good.