this game could be epic for pvp.
you could raid each others bases, or work together to create an arena with whatever going on in it.
However I recommend you do not loot each other. You can, but doing that costs the loser hours or even days of work. The PVE idea was that if you die, you have to recover your body by stealth or backup gear or get help or whatever, and nothing is really lost but time and aggravation. But PVP, if you take the other guy's stuff, its gone for good and gathering the materials to get it back is exceedingly brutal at the higher levels.

I also suggest you have house-rules that you agree upon, like whether you break up the other player's home or loot their storage chests or grief them when they are not home or whatnot. Or no epic stupidity like falling forever through a portal pair. Stuff like that is funny, once, but too much of it can ruin your experiences.

I would say that with some ground rules and friendly cooperation, you will have a great time with this.