Both LG and Samsung are two of the most loved and hated smartphone brands when it comes to software. They cover stock Android with a custom skin, fill it with features that are often times useless, and it slows things down.
That said, over the past few years, both companies have vastly improved this situation. Some feel Samsung made the biggest changes, while others seem to enjoy the tweaks offered by LG.
Either way, these phones are going to be fast. With the latest software and cutting edge hardware, you can just expect performance to be pretty great. One big aspect is whether or not the LG V30 launches with Android 8.0, like the V20 did Android 7.0 Nougat. It was the first phone to arrive with Google's new software. With Android 8.0 Oreo already out, LG could beat everyone to the punch.
As for battery life, we're hearing both phones have the same 3,300 mAh battery inside. Samsung already confirmed as much, so we'll wait for LG's announcement before saying anything further.
One thing to keep in mind is that if both phones have the same size 3,300 mAh battery, the smaller LG V30 should technically have the better battery life. It should, but that doesn't mean it will. And again, that battery is not removable.