Whether it is any better in any respect other than size/weight depends on the pack you get.
Since many of the cheap ones are literally recycled garbage, you would want to buy from a reputable seller / manufacturer to avoid that. The cheaper it is the less likely it is to be any better (or even as good as) what you have already. The less info the seller is willing to provide, the less likely...etc.
You also must make sure the pack is designed to handle the peak and continous currents your system requires. If you don't know what those are, you can check the bike's manufacturer info to see if they tell you. If not, you can see if there is a label on the controller with this info. If not, you would want to get a wattmeter and install it in the system (to make it easy to get ride data without having to watch it all the time), or use a clamp-on current meter (ammeter) if you can set that up where you can see it and watch it while you ride and write down the readings you get.
Assuming you get a pack designed to handle at least as much power as the bike will require to operate the way you ride it, then it will have more range and a longer lifespan than the lead pack you have now. How much more range, and how much longer lifespan, depends on the specifics of the pack vs the way you use it on the bike.
