I heartily agree with their fountain pen choices. The Pilot Metropolitan is insanely good for a cheap pen that you can take anywhere and the TWSBI GO is my go-to daily driver. It leads me to believe that the rest of the reviews are likely good.
I bought a moonman m2 a long time ago and really love it but also if I travel with it I end up bringing a whole cleanup kit because even with care I tend to have at least once where ink comes out into the cap. Is this just a fact of life with fountain pens in general? I love the writing but keeping them clean & operational has been non-trivial for me.
Otherwise, ink shouldn't come out unless there is a flaw in the pen (which many ultra cheap pens have).
I've not tried the Moonman, but Jinhao/PenBBS are solid for me. Rarely do they "leak".