Really. I didnt think that it was hard to spike. I learned it in just a few days after watching some old melee matches.
This is a trick that i use in some cases:
If you know or have a feeling that it will just be a suicide becouse it takes to long to recover, use the second jump right before you attack. That way you wont get stunned and take time to recover, becouse you are going upwards insted of downwards, making it possible to instantly get back to the stage.
I do this most of the times, but as i have learned how to use spike properly i sometimes go for a suicide kill when the opponent have one stock left, the only problem with this is that i loose if i miss, but that rarely happens.
So for last stock (or when i have alot of damage!) i do a suicide spike so both of us die, but the opponent dies first.
When my opponents have more then one stock and i have a small amount of damage i go for a safe spike by saving one of the jumps for the spike.