So I was initially hesitant when I got this saber, but I can safely say I am very satisfied. Access to the core is simple. The activation button is a two part system with the inner part working as a plunger button. As for the core, I have mine installed with a Proffie core. A little tip: be sure to use a core that is not as long. My personal recommendation is to use a golden specialty core (the ones that have a USB-C charging port towards the base of the core). If you are looking for a cheaper alternative to the ones by LGT and TXQ, the Ruin Eco is a must have.

I’ve been battling with my girlfriend with her lightsaber and we’ve been having a blast :)

Terrible for dueling. there are a bunch of design ellements that are questionable.
Like the placement of the set screw as well as the placement of the break down point where the grip screws to the emitter, this is a weak point right in the center of the hilt. I don't feel safe using this saber for dueling or even spinning. Only useable for display and for that purpose aslone it is way too expencive. very dissapointed.

Adam has to take the batteries out and put them back in another Sabre to charge them...why!?

This hilt is very well made and has the screen-accuracy features that versions made by other producers lack. The main difference of this hilt comes from the screws on the 3 claws and the 2 accent elements on the pommel area, but I personally really like those screws being there.
The hilt being in 2 major pieces is a really useful feature and allows for many different install options. However, the standard option of using a drop-in core is a very solid and cost-effective one.
Overall, I am very happy with this hilt and happily recommend it to anyone interested!