Top speed = fast. I'm the wrong guy to answer this question, but I don't see it struggling to crack 30 at all. Thing is, I've had several bikes that could easily crack 30mph now, so that novelty is gone. From what I've seen/read about, I'm not the only one in that same boat. When you see what speeds over about 15 mph do to your battery mileage (due to wind resistance among other things), they become tough to justify.
The controller is built into the motor, Bafang makes it, and they have a pretty good reputation. However, if you're inclined to abuse it with something like a wide open take off from a standing start in high gear, or maybe climbing a long steep hill in too high a gear, it IS possible to overheat/blow them. The motor is thermally protected, designed to shut down if it gets hot.
The really nice thing about the Ultra, to this rider/tinkerer, is that I can hook it up to a laptop and customize any piece of it I want. It's completely unlocked (a rare feature in my experience). Everything from required pedal effort, the amount of power it gets when first applying throttle, amount of power allowed in each PAS level, ALL OF IT, is completely customizable. If that's not enough, there are some aftermarket controllers available. Not cheap by any imagination (think 1000.), but written so the software controlling the motor is state of the art, as well as the components used to build it.
You can password protect the bike using the LCD display if you like, but that's not a real secure way to prevent theft. At best, they'll still be able to ride the bike away un-powered. My bike is either locked up in my garage when I'm not on it, or locked to a small utility trailer I use to move my bike and the wife's to local scenic trails for rides there. So no, I don't use that built in "security".
The Ultra powered bikes have over the top power, the most available anywhere to my understanding. So yes, it's going to climb any hill you point it at. If you can't make a hill, it's because YOU screwed up. The bike will be perfectly willing.
I shopped for a couple of months prior to settling on the Rize. Looked at all sorts of stuff, including belt drives. In the end, the belt driven transmissions scared me. Those eliminated, I worked on a bucks spent for bang received as I could care less about "support". I do all of my own work anyway. So, bucks spent for bang received, I found the Ultra powered Rize tough to beat.... -Al