I recently made the switch from insufflation to sublingual administration. I now see no reason to insufflate.
Insufflation maybe has a slightly faster onset, but because the come-up phase of a methoxetamine trip is so enchanting, I see this as a virtue of sublingual admin. In any case, I always deliberately prolong the come-up phase by staggering my dosage.
Sublingual dosage seems slightly more potent. 50 mg sublingual MXE seems equipotent to, say, 65 mg insufflated MXE.
Insufflation makes my nasal passages dry.
Most importantly, the high of sublingually-dosed MXE seems cleaner, with slightly less confusion and disorientation to distract from the desirable effects. Such qualitative differences are a bit hard to judge, because each trip is unique, but this is my perception.
I'm getting damn good at sublingual admin., too. I used to have difficulty holding the chemical in place without allowing my saliva to wash it out from under my tongue, which was both wasteful and tasted bitter. Now, I can keep a dose under my tongue for a good ten minutes without tasting so much as a hint of leakage.