This is an old thread but i feel i have to put in my 2 cents. Before I had even ever used and experimented with crystal i always heard and read the same story and i can confirm with 100% accuracy that essentially;
Snorting : gives a very speedy and tweaked out high, perfect for dancing
Smoking : gives a sudden rush but ‘chill’ high that makes you just wanna talk and lay in a group cuddle (like pure mdma)
Oral : takes longer to hit but gives the strongest ‘ooomf!!’ And punch while having the longest duration and highest/longest peak
Rectal : similar to oral but takes effect faster and fades out sooner, gives the least painful crash/come down imo. Best for nights alone at home
IV : gives a fiery body/head rush similar but also very different from cocaine, almost like a combination of oral and snorted. Fades out the quickest and has the harshest comedown. Best for tweaker pads and making shitty environments seem magical
In conclusion, I would most recommend snorting and smoking, in that order.