I have several of these and use them all the time.
They are great for power when my house goes out which seems to be more and more frequent.
I would get the cheapest one with the highest battery
If you look on the packaging it will say how large a battery
They mostly use either 7 to 9 ah or 18 to 20ah batteries.
The case it is in can deceive you though about the size of the battery so try for the bigger one.
As a reference I pay around $20.00 for the 18ah batteries in these things from a Burglar Alarm distributor and you might pay 2 or 3 times that at retail for them.
So far I really like the ones where you can turn off the jumper cables with a switch so I don't have to worry about touching thhem to anything for unexpected fireworks.
They all use Seald Lead Acid batteries are seem fairly rugged. I use them foe emergency radio communications and they last a long time.
I also have run my trailer with them and small T.V,s too.
Actually I can not imagine not having them around for the right price.