I personally prefer DEP Notify but had good success with SplashBuddy early on (education BYOD and DEP). If I were to move back in that direction I would probably choose octory.io (The paid/commercial version of SplashBuddy). For now, I am sticking with DEPNotify as we're headed toward JAMF Connect and want to utilize that set of tools more directly.
I personally found that SplashBuddy required more steps for me to configure than DEPNotify, but I am simple and utilized the DEPNotify Starter scripts and moved on from there. In the end, for us, DEPNotify is simply faster, and in my opinion, easier to reconfigure. That said, I haven't used it in two years and I've never used octory at all (Outside of test/demo).
