I smoked resin several times and found it to be less effective than ingestion. I gave up in the end as I was worried about my lungs - and turned to melting it in water. The plus side of smoking was no nausea - but if you're ingesting you can avoid nausea with careful dosing. Personally, I think the potential harm from smoking Kratom way outweighs the benefit.
Having said this - I never tried vaping....