Project Farm tested a few recently. I like the capacitor one the best, less need to keep it charged, but I don't think it'd handle our glow plugs at all.
https://www.youtube.com/watch?v=JN8A2nIMUWA
https://www.youtube.com/watch?v=ixWPx79g3yk
I have an off brand jump starter pack, it jumped a buddy's motorcycle just fine but wouldn't even try to crank over my 13hp Generac engine in my generator. Maybe it needs to sense some level of battery voltage before it'll do anything, and it was the only battery in the system on the Generac. I would not rely on it for anything but charging a cellphone.
On the flip side, with the larger battery and 150a continuous duty alternator, I've been able to jump start much larger vehicles than a lil Yota normally would be able to. 7.3l diesel without much trouble, and with half an hour of idling and charging we were able to get a buddy's semi truck started.