From what I could tell based on the amount of dirt in the bin, the i7+ cleaned up my floors and carpets just as well as the 980. iRobot says it has twice the suction power of the Roomba 960, but it lacks the loud Power Boost feature from the 980. That's not a huge loss, though, especially since the i7+ is something I don't mind running more often.
Its navigation and mapping technology hasn't changed, but it still does a solid job of avoiding obstacles and navigating along floors and walls. After one cleaning job, the i7+ had a basic sketch of my apartment's layout (which you can view on the iRobot app), but it took four rounds of work before it had a completed map (see below). Once it has the lay of the land, you can also label rooms, which lets you command Roomba (either through Alexa or the app) to clean a specific area.
It took the Roomba i7+ 65 minutes to complete a full pass of my two-bedroom apartment. That might sound like a lengthy run, but it's the same amount of time that it took the 980. I'd much rather have a robot vacuum that did a thorough job of cleaning as much cat hair as possible, no matter how long it took, than try to race through my home.
The i7+ always managed to find its way back to its Clean Base when it was done, but for some reason it forgot to vacuum out the dirt bin after the first job. That's not a huge deal, since you can do that by hitting a button on the mobile app, but it was still annoying. Automated self-cleaning is the entire selling point of this machine, after all. I'll chalk that up as a first-run error, since the i7+ faithfully emptied itself after every future cleaning job.
So how, exactly, does the i7+ clear its own bin? It's all about the Clean Base: iRobot placed a vacuum intake at the bottom, which connects to an opening underneath the Roomba's dust tray. You also have the option of manually opening the bin, just in case you're worried a piece of jewelry was sucked up. iRobot claims the Base's proprietary bag can hold up to 30 bins worth of dirt. Once it's full, you just have to open the top of the base and throw the bag in the trash. While it's a shame that such an expensive vacuum requires a constant outlay of cash for new bags (they're $15 for a pack of three), at least you won't have to change them often.
I've lived with the Roomba i7+ for a few weeks now, and in that time I've used it far more frequently than other robot vacuums. That alone is telling. The combination of quiet performance, smart navigation and automatic bin cleaning reduces most of the friction I've experienced with other models. I didn't even worry as much about toys and cables on the floor -- the i7+ is smart enough to untangle itself by running its rollers backward. Previous models needed constant babysitting, but this only got stuck once, underneath my dining table.