which is better triplus or rapidus?

[Arcon]

True, but the first time you see the message, you will always see your TH level +1. As a TH6, my first message is always a level 7 effect.

That's because it doesn't say when TH is applied, only when it's upgraded. So with TH6, you put it on and get no message, it's still on though. And only when a melee hit upgrades it, you get a message. This can be proven easily, get TH on with TH6, then unequip all TH gear. The next upgrade will still be to TH7, which means TH6 was on before, even though you didn't have gear for it.